[Stats] Attribute::ToString(), to replace member ValueToString/ToJson.
Delete RTCStatsMember<T>::ValueToString() and ValueToJson() in favor of
Attribute::ToString().
The difference between "ToString" and "ToJson" is that the "ToJson"
version converts 64-bit integers and doubles to floating points with no
more than ~15 digits of precision as to not exceed JSON's precision
limitations. So only in edge cases of really large numbers or numbers
with a silly number of digits will the two methods produce different
results. Also JSON puts '\"' around map key names, e.g. "{\"foo\":123}"
as opposed to "{foo:123}".
Going forward we see no reason to maintain two different string
converted paths that are this similar, so we only implement one
Attribute::ToString() method which does what "ToJson" did.
In the next CL we can delete RTCStatsMember<T>.
Bug: webrtc:15164
Change-Id: Iaa8cf3bf14b40dc44664f75989832469603131c5
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/334640
Commit-Queue: Henrik Boström <hbos@webrtc.org>
Reviewed-by: Evan Shrubsole <eshr@google.com>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#41544}
diff --git a/api/stats/attribute.h b/api/stats/attribute.h
index fdedc74..dd21a98 100644
--- a/api/stats/attribute.h
+++ b/api/stats/attribute.h
@@ -74,8 +74,11 @@
bool is_sequence() const;
bool is_string() const;
- std::string ValueToString() const;
- std::string ValueToJson() const;
+ // Converts the attribute to a string that is parseable as a JSON object.
+ std::string ToString() const;
+ // TODO(https://crbug.com/15164): Use ToString() instead and delete these.
+ std::string ValueToString() const { return ToString(); }
+ std::string ValueToJson() const { return ToString(); }
bool operator==(const Attribute& other) const;
bool operator!=(const Attribute& other) const;
diff --git a/api/stats/rtc_stats_member.h b/api/stats/rtc_stats_member.h
index d2aa539..bf9cc0f 100644
--- a/api/stats/rtc_stats_member.h
+++ b/api/stats/rtc_stats_member.h
@@ -65,13 +65,6 @@
bool operator!=(const RTCStatsMemberInterface& other) const {
return !(*this == other);
}
- virtual std::string ValueToString() const = 0;
- // This is the same as ValueToString except for kInt64 and kUint64 types,
- // where the value is represented as a double instead of as an integer.
- // Since JSON stores numbers as floating point numbers, very large integers
- // cannot be accurately represented, so we prefer to display them as doubles
- // instead.
- virtual std::string ValueToJson() const = 0;
virtual const RTCStatsMemberInterface* member_ptr() const { return this; }
template <typename T>
@@ -98,8 +91,6 @@
bool is_sequence() const override;
bool is_string() const override;
bool is_defined() const override { return value_.has_value(); }
- std::string ValueToString() const override;
- std::string ValueToJson() const override;
template <typename U>
inline T value_or(U default_value) const {
@@ -170,10 +161,6 @@
RTC_EXPORT bool RTCStatsMember<T>::is_sequence() const; \
template <> \
RTC_EXPORT bool RTCStatsMember<T>::is_string() const; \
- template <> \
- RTC_EXPORT std::string RTCStatsMember<T>::ValueToString() const; \
- template <> \
- RTC_EXPORT std::string RTCStatsMember<T>::ValueToJson() const; \
extern template class RTC_EXPORT_TEMPLATE_DECLARE(RTC_EXPORT) \
RTCStatsMember<T>
diff --git a/pc/peer_connection_rampup_tests.cc b/pc/peer_connection_rampup_tests.cc
index 0fd3c27..e45821b 100644
--- a/pc/peer_connection_rampup_tests.cc
+++ b/pc/peer_connection_rampup_tests.cc
@@ -313,7 +313,9 @@
return 0;
}
std::string selected_ice_id =
- transport_stats[0]->selected_candidate_pair_id.ValueToString();
+ transport_stats[0]
+ ->GetAttribute(transport_stats[0]->selected_candidate_pair_id)
+ .ToString();
// Use the selected ICE candidate pair ID to get the appropriate ICE stats.
const RTCIceCandidatePairStats ice_candidate_pair_stats =
stats->Get(selected_ice_id)->cast_to<const RTCIceCandidatePairStats>();
diff --git a/pc/rtc_stats_integrationtest.cc b/pc/rtc_stats_integrationtest.cc
index 762dad6..002f9d3 100644
--- a/pc/rtc_stats_integrationtest.cc
+++ b/pc/rtc_stats_integrationtest.cc
@@ -228,9 +228,10 @@
template <typename T>
void TestAttributeIsUndefined(const RTCStatsMember<T>& field) {
+ Attribute attribute = stats_->GetAttribute(field);
EXPECT_FALSE(field.has_value())
- << stats_->type() << "." << stats_->GetAttribute(field).name() << "["
- << stats_->id() << "] was defined (" << field.ValueToString() << ").";
+ << stats_->type() << "." << attribute.name() << "[" << stats_->id()
+ << "] was defined (" << attribute.ToString() << ").";
MarkAttributeTested(field, !field.has_value());
}
@@ -246,7 +247,7 @@
bool is_positive = field.value() > T(0);
EXPECT_TRUE(is_positive)
<< stats_->type() << "." << attribute.name() << "[" << stats_->id()
- << "] was not positive (" << attribute.ValueToString() << ").";
+ << "] was not positive (" << attribute.ToString() << ").";
MarkAttributeTested(field, is_positive);
}
@@ -262,7 +263,7 @@
bool is_non_negative = field.value() >= T(0);
EXPECT_TRUE(is_non_negative)
<< stats_->type() << "." << attribute.name() << "[" << stats_->id()
- << "] was not non-negative (" << attribute.ValueToString() << ").";
+ << "] was not non-negative (" << attribute.ToString() << ").";
MarkAttributeTested(field, is_non_negative);
}
@@ -323,8 +324,7 @@
<< stats_->type() << "." << attribute.name()
<< " is not a reference to an "
"existing dictionary of type "
- << expected_type << " (value: "
- << (field.has_value() ? attribute.ValueToString() : "null") << ").";
+ << expected_type << " (value: " << attribute.ToString() << ").";
MarkAttributeTested(field, valid_reference);
}
diff --git a/stats/attribute.cc b/stats/attribute.cc
index 76956e2..fab948b 100644
--- a/stats/attribute.cc
+++ b/stats/attribute.cc
@@ -10,8 +10,13 @@
#include "api/stats/attribute.h"
+#include <string>
+
#include "absl/types/variant.h"
+#include "rtc_base/arraysize.h"
#include "rtc_base/checks.h"
+#include "rtc_base/string_encode.h"
+#include "rtc_base/strings/string_builder.h"
namespace webrtc {
@@ -30,6 +35,82 @@
}
};
+// Converts the attribute to string in a JSON-compatible way.
+struct VisitToString {
+ template <typename T,
+ typename std::enable_if_t<
+ std::is_same_v<T, int32_t> || std::is_same_v<T, uint32_t> ||
+ std::is_same_v<T, bool> || std::is_same_v<T, std::string>,
+ bool> = true>
+ std::string ValueToString(const T& value) {
+ return rtc::ToString(value);
+ }
+ // Convert 64-bit integers to doubles before converting to string because JSON
+ // represents all numbers as floating points with ~15 digits of precision.
+ template <typename T,
+ typename std::enable_if_t<std::is_same_v<T, int64_t> ||
+ std::is_same_v<T, uint64_t> ||
+ std::is_same_v<T, double>,
+ bool> = true>
+ std::string ValueToString(const T& value) {
+ char buf[32];
+ const int len = std::snprintf(&buf[0], arraysize(buf), "%.16g",
+ static_cast<double>(value));
+ RTC_DCHECK_LE(len, arraysize(buf));
+ return std::string(&buf[0], len);
+ }
+
+ // Vector attributes.
+ template <typename T>
+ std::string operator()(const RTCStatsMember<std::vector<T>>* attribute) {
+ rtc::StringBuilder sb;
+ sb << "[";
+ const char* separator = "";
+ constexpr bool element_is_string = std::is_same<T, std::string>::value;
+ for (const T& element : attribute->value()) {
+ sb << separator;
+ if (element_is_string) {
+ sb << "\"";
+ }
+ sb << ValueToString(element);
+ if (element_is_string) {
+ sb << "\"";
+ }
+ separator = ",";
+ }
+ sb << "]";
+ return sb.Release();
+ }
+ // Map attributes.
+ template <typename T>
+ std::string operator()(
+ const RTCStatsMember<std::map<std::string, T>>* attribute) {
+ rtc::StringBuilder sb;
+ sb << "{";
+ const char* separator = "";
+ constexpr bool element_is_string = std::is_same<T, std::string>::value;
+ for (const auto& pair : attribute->value()) {
+ sb << separator;
+ sb << "\"" << pair.first << "\":";
+ if (element_is_string) {
+ sb << "\"";
+ }
+ sb << ValueToString(pair.second);
+ if (element_is_string) {
+ sb << "\"";
+ }
+ separator = ",";
+ }
+ sb << "}";
+ return sb.Release();
+ }
+ // Simple attributes.
+ template <typename T>
+ std::string operator()(const RTCStatsMember<T>* attribute) {
+ return ValueToString(attribute->value());
+ }
+};
+
struct VisitIsEqual {
template <typename T>
bool operator()(const RTCStatsMember<T>* attribute) {
@@ -69,14 +150,11 @@
attribute_);
}
-std::string Attribute::ValueToString() const {
- return absl::visit([](const auto* attr) { return attr->ValueToString(); },
- attribute_);
-}
-
-std::string Attribute::ValueToJson() const {
- return absl::visit([](const auto* attr) { return attr->ValueToJson(); },
- attribute_);
+std::string Attribute::ToString() const {
+ if (!has_value()) {
+ return "null";
+ }
+ return absl::visit(VisitToString(), attribute_);
}
bool Attribute::operator==(const Attribute& other) const {
diff --git a/stats/rtc_stats.cc b/stats/rtc_stats.cc
index ea87379b..e7d72ee 100644
--- a/stats/rtc_stats.cc
+++ b/stats/rtc_stats.cc
@@ -54,8 +54,7 @@
if (attribute.holds_alternative<std::string>()) {
sb << "\"";
}
- sb << absl::visit([](const auto* attr) { return attr->ValueToJson(); },
- attribute.as_variant());
+ sb << attribute.ToString();
if (attribute.holds_alternative<std::string>()) {
sb << "\"";
}
diff --git a/stats/rtc_stats_member.cc b/stats/rtc_stats_member.cc
index d7a3f6c..3f91988 100644
--- a/stats/rtc_stats_member.cc
+++ b/stats/rtc_stats_member.cc
@@ -10,231 +10,53 @@
#include "api/stats/rtc_stats_member.h"
-#include "rtc_base/arraysize.h"
-#include "rtc_base/strings/string_builder.h"
-
namespace webrtc {
-namespace {
-
-// Produces "[a,b,c]". Works for non-vector `RTCStatsMemberInterface::Type`
-// types.
-template <typename T>
-std::string VectorToString(const std::vector<T>& vector) {
- rtc::StringBuilder sb;
- sb << "[";
- const char* separator = "";
- for (const T& element : vector) {
- sb << separator << rtc::ToString(element);
- separator = ",";
- }
- sb << "]";
- return sb.Release();
-}
-
-// This overload is required because std::vector<bool> range loops don't
-// return references but objects, causing -Wrange-loop-analysis diagnostics.
-std::string VectorToString(const std::vector<bool>& vector) {
- rtc::StringBuilder sb;
- sb << "[";
- const char* separator = "";
- for (bool element : vector) {
- sb << separator << rtc::ToString(element);
- separator = ",";
- }
- sb << "]";
- return sb.Release();
-}
-
-// Produces "[\"a\",\"b\",\"c\"]". Works for vectors of both const char* and
-// std::string element types.
-template <typename T>
-std::string VectorOfStringsToString(const std::vector<T>& strings) {
- rtc::StringBuilder sb;
- sb << "[";
- const char* separator = "";
- for (const T& element : strings) {
- sb << separator << "\"" << rtc::ToString(element) << "\"";
- separator = ",";
- }
- sb << "]";
- return sb.Release();
-}
-
-template <typename T>
-std::string MapToString(const std::map<std::string, T>& map) {
- rtc::StringBuilder sb;
- sb << "{";
- const char* separator = "";
- for (const auto& element : map) {
- sb << separator << rtc::ToString(element.first) << ":"
- << rtc::ToString(element.second);
- separator = ",";
- }
- sb << "}";
- return sb.Release();
-}
-
-template <typename T>
-std::string ToStringAsDouble(const T value) {
- // JSON represents numbers as floating point numbers with about 15 decimal
- // digits of precision.
- char buf[32];
- const int len = std::snprintf(&buf[0], arraysize(buf), "%.16g",
- static_cast<double>(value));
- RTC_DCHECK_LE(len, arraysize(buf));
- return std::string(&buf[0], len);
-}
-
-template <typename T>
-std::string VectorToStringAsDouble(const std::vector<T>& vector) {
- rtc::StringBuilder sb;
- sb << "[";
- const char* separator = "";
- for (const T& element : vector) {
- sb << separator << ToStringAsDouble<T>(element);
- separator = ",";
- }
- sb << "]";
- return sb.Release();
-}
-
-template <typename T>
-std::string MapToStringAsDouble(const std::map<std::string, T>& map) {
- rtc::StringBuilder sb;
- sb << "{";
- const char* separator = "";
- for (const auto& element : map) {
- sb << separator << "\"" << rtc::ToString(element.first)
- << "\":" << ToStringAsDouble(element.second);
- separator = ",";
- }
- sb << "}";
- return sb.Release();
-}
-
-} // namespace
-
-#define WEBRTC_DEFINE_RTCSTATSMEMBER(T, type, is_seq, is_str, to_str, to_json) \
- template <> \
- RTCStatsMemberInterface::Type RTCStatsMember<T>::StaticType() { \
- return type; \
- } \
- template <> \
- bool RTCStatsMember<T>::is_sequence() const { \
- return is_seq; \
- } \
- template <> \
- bool RTCStatsMember<T>::is_string() const { \
- return is_str; \
- } \
- template <> \
- std::string RTCStatsMember<T>::ValueToString() const { \
- RTC_DCHECK(value_.has_value()); \
- return to_str; \
- } \
- template <> \
- std::string RTCStatsMember<T>::ValueToJson() const { \
- RTC_DCHECK(value_.has_value()); \
- return to_json; \
- } \
+#define WEBRTC_DEFINE_RTCSTATSMEMBER(T, type, is_seq, is_str) \
+ template <> \
+ RTCStatsMemberInterface::Type RTCStatsMember<T>::StaticType() { \
+ return type; \
+ } \
+ template <> \
+ bool RTCStatsMember<T>::is_sequence() const { \
+ return is_seq; \
+ } \
+ template <> \
+ bool RTCStatsMember<T>::is_string() const { \
+ return is_str; \
+ } \
template class RTC_EXPORT_TEMPLATE_DEFINE(RTC_EXPORT) RTCStatsMember<T>
-WEBRTC_DEFINE_RTCSTATSMEMBER(bool,
- kBool,
- false,
- false,
- rtc::ToString(*value_),
- rtc::ToString(*value_));
-WEBRTC_DEFINE_RTCSTATSMEMBER(int32_t,
- kInt32,
- false,
- false,
- rtc::ToString(*value_),
- rtc::ToString(*value_));
-WEBRTC_DEFINE_RTCSTATSMEMBER(uint32_t,
- kUint32,
- false,
- false,
- rtc::ToString(*value_),
- rtc::ToString(*value_));
-WEBRTC_DEFINE_RTCSTATSMEMBER(int64_t,
- kInt64,
- false,
- false,
- rtc::ToString(*value_),
- ToStringAsDouble(*value_));
-WEBRTC_DEFINE_RTCSTATSMEMBER(uint64_t,
- kUint64,
- false,
- false,
- rtc::ToString(*value_),
- ToStringAsDouble(*value_));
-WEBRTC_DEFINE_RTCSTATSMEMBER(double,
- kDouble,
- false,
- false,
- rtc::ToString(*value_),
- ToStringAsDouble(*value_));
-WEBRTC_DEFINE_RTCSTATSMEMBER(std::string,
- kString,
- false,
- true,
- *value_,
- *value_);
-WEBRTC_DEFINE_RTCSTATSMEMBER(std::vector<bool>,
- kSequenceBool,
- true,
- false,
- VectorToString(*value_),
- VectorToString(*value_));
-WEBRTC_DEFINE_RTCSTATSMEMBER(std::vector<int32_t>,
- kSequenceInt32,
- true,
- false,
- VectorToString(*value_),
- VectorToString(*value_));
+WEBRTC_DEFINE_RTCSTATSMEMBER(bool, kBool, false, false);
+WEBRTC_DEFINE_RTCSTATSMEMBER(int32_t, kInt32, false, false);
+WEBRTC_DEFINE_RTCSTATSMEMBER(uint32_t, kUint32, false, false);
+WEBRTC_DEFINE_RTCSTATSMEMBER(int64_t, kInt64, false, false);
+WEBRTC_DEFINE_RTCSTATSMEMBER(uint64_t, kUint64, false, false);
+WEBRTC_DEFINE_RTCSTATSMEMBER(double, kDouble, false, false);
+WEBRTC_DEFINE_RTCSTATSMEMBER(std::string, kString, false, true);
+WEBRTC_DEFINE_RTCSTATSMEMBER(std::vector<bool>, kSequenceBool, true, false);
+WEBRTC_DEFINE_RTCSTATSMEMBER(std::vector<int32_t>, kSequenceInt32, true, false);
WEBRTC_DEFINE_RTCSTATSMEMBER(std::vector<uint32_t>,
kSequenceUint32,
true,
- false,
- VectorToString(*value_),
- VectorToString(*value_));
-WEBRTC_DEFINE_RTCSTATSMEMBER(std::vector<int64_t>,
- kSequenceInt64,
- true,
- false,
- VectorToString(*value_),
- VectorToStringAsDouble(*value_));
+ false);
+WEBRTC_DEFINE_RTCSTATSMEMBER(std::vector<int64_t>, kSequenceInt64, true, false);
WEBRTC_DEFINE_RTCSTATSMEMBER(std::vector<uint64_t>,
kSequenceUint64,
true,
- false,
- VectorToString(*value_),
- VectorToStringAsDouble(*value_));
-WEBRTC_DEFINE_RTCSTATSMEMBER(std::vector<double>,
- kSequenceDouble,
- true,
- false,
- VectorToString(*value_),
- VectorToStringAsDouble(*value_));
+ false);
+WEBRTC_DEFINE_RTCSTATSMEMBER(std::vector<double>, kSequenceDouble, true, false);
WEBRTC_DEFINE_RTCSTATSMEMBER(std::vector<std::string>,
kSequenceString,
true,
- false,
- VectorOfStringsToString(*value_),
- VectorOfStringsToString(*value_));
+ false);
WEBRTC_DEFINE_RTCSTATSMEMBER(rtc_stats_internal::MapStringUint64,
kMapStringUint64,
false,
- false,
- MapToString(*value_),
- MapToStringAsDouble(*value_));
+ false);
WEBRTC_DEFINE_RTCSTATSMEMBER(rtc_stats_internal::MapStringDouble,
kMapStringDouble,
false,
- false,
- MapToString(*value_),
- MapToStringAsDouble(*value_));
+ false);
} // namespace webrtc
diff --git a/stats/rtc_stats_unittest.cc b/stats/rtc_stats_unittest.cc
index 8837da7..40b05d7 100644
--- a/stats/rtc_stats_unittest.cc
+++ b/stats/rtc_stats_unittest.cc
@@ -459,45 +459,50 @@
EXPECT_FALSE(stats.m_map_string_double.is_string());
}
-TEST(RTCStatsTest, ValueToString) {
+TEST(RTCStatsTest, AttributeToString) {
RTCTestStats stats("statsId", Timestamp::Micros(42));
stats.m_bool = true;
- EXPECT_EQ("true", stats.m_bool.ValueToString());
+ EXPECT_EQ("true", stats.GetAttribute(stats.m_bool).ToString());
stats.m_string = "foo";
- EXPECT_EQ("foo", stats.m_string.ValueToString());
+ EXPECT_EQ("foo", stats.GetAttribute(stats.m_string).ToString());
stats.m_int32 = -32;
- EXPECT_EQ("-32", stats.m_int32.ValueToString());
+ EXPECT_EQ("-32", stats.GetAttribute(stats.m_int32).ToString());
stats.m_uint32 = 32;
- EXPECT_EQ("32", stats.m_uint32.ValueToString());
+ EXPECT_EQ("32", stats.GetAttribute(stats.m_uint32).ToString());
stats.m_int64 = -64;
- EXPECT_EQ("-64", stats.m_int64.ValueToString());
+ EXPECT_EQ("-64", stats.GetAttribute(stats.m_int64).ToString());
stats.m_uint64 = 64;
- EXPECT_EQ("64", stats.m_uint64.ValueToString());
+ EXPECT_EQ("64", stats.GetAttribute(stats.m_uint64).ToString());
stats.m_double = 0.5;
- EXPECT_EQ("0.5", stats.m_double.ValueToString());
+ EXPECT_EQ("0.5", stats.GetAttribute(stats.m_double).ToString());
stats.m_sequence_bool = {true, false};
- EXPECT_EQ("[true,false]", stats.m_sequence_bool.ValueToString());
+ EXPECT_EQ("[true,false]",
+ stats.GetAttribute(stats.m_sequence_bool).ToString());
stats.m_sequence_int32 = {-32, 32};
- EXPECT_EQ("[-32,32]", stats.m_sequence_int32.ValueToString());
+ EXPECT_EQ("[-32,32]", stats.GetAttribute(stats.m_sequence_int32).ToString());
stats.m_sequence_uint32 = {64, 32};
- EXPECT_EQ("[64,32]", stats.m_sequence_uint32.ValueToString());
+ EXPECT_EQ("[64,32]", stats.GetAttribute(stats.m_sequence_uint32).ToString());
stats.m_sequence_int64 = {-64, 32};
- EXPECT_EQ("[-64,32]", stats.m_sequence_int64.ValueToString());
+ EXPECT_EQ("[-64,32]", stats.GetAttribute(stats.m_sequence_int64).ToString());
stats.m_sequence_uint64 = {16, 32};
- EXPECT_EQ("[16,32]", stats.m_sequence_uint64.ValueToString());
+ EXPECT_EQ("[16,32]", stats.GetAttribute(stats.m_sequence_uint64).ToString());
stats.m_sequence_double = {0.5, 0.25};
- EXPECT_EQ("[0.5,0.25]", stats.m_sequence_double.ValueToString());
+ EXPECT_EQ("[0.5,0.25]",
+ stats.GetAttribute(stats.m_sequence_double).ToString());
stats.m_sequence_string = {"foo", "bar"};
- EXPECT_EQ("[\"foo\",\"bar\"]", stats.m_sequence_string.ValueToString());
+ EXPECT_EQ("[\"foo\",\"bar\"]",
+ stats.GetAttribute(stats.m_sequence_string).ToString());
stats.m_map_string_uint64 = std::map<std::string, uint64_t>();
stats.m_map_string_uint64->emplace("foo", 32);
stats.m_map_string_uint64->emplace("bar", 64);
- EXPECT_EQ("{bar:64,foo:32}", stats.m_map_string_uint64.ValueToString());
+ EXPECT_EQ("{\"bar\":64,\"foo\":32}",
+ stats.GetAttribute(stats.m_map_string_uint64).ToString());
stats.m_map_string_double = std::map<std::string, double>();
stats.m_map_string_double->emplace("foo", 0.5);
stats.m_map_string_double->emplace("bar", 0.25);
- EXPECT_EQ("{bar:0.25,foo:0.5}", stats.m_map_string_double.ValueToString());
+ EXPECT_EQ("{\"bar\":0.25,\"foo\":0.5}",
+ stats.GetAttribute(stats.m_map_string_double).ToString());
}
// Death tests.
diff --git a/test/pc/e2e/analyzer/video/video_quality_metrics_reporter.cc b/test/pc/e2e/analyzer/video/video_quality_metrics_reporter.cc
index 3ae7fda..e666241 100644
--- a/test/pc/e2e/analyzer/video/video_quality_metrics_reporter.cc
+++ b/test/pc/e2e/analyzer/video/video_quality_metrics_reporter.cc
@@ -63,7 +63,9 @@
}
RTC_DCHECK_EQ(transport_stats.size(), 1);
std::string selected_ice_id =
- transport_stats[0]->selected_candidate_pair_id.ValueToString();
+ transport_stats[0]
+ ->GetAttribute(transport_stats[0]->selected_candidate_pair_id)
+ .ToString();
// Use the selected ICE candidate pair ID to get the appropriate ICE stats.
const RTCIceCandidatePairStats ice_candidate_pair_stats =
report->Get(selected_ice_id)->cast_to<const RTCIceCandidatePairStats>();
