Rename two latency with proper names

Summary: Make the code easier to read and search.

Reviewed By: islamismailov

Differential Revision: D73374259

fbshipit-source-id: 8c6ee44da82325c5d177e9231fddf4579f4c13b8

Author: tlj77

third-party/thrift/src/thrift/lib/cpp2/async/RequestCallback.h

@@ -48,8 +48,8 @@ struct RpcTransportStats {
   uint32_t responseWireSizeBytes{0};
 
   // I/O latencies
-  std::chrono::nanoseconds requestLatency{0};
-  std::chrono::nanoseconds responseLatency{0};
+  std::chrono::nanoseconds requestWriteLatency{0};
+  std::chrono::nanoseconds responseRoundTripLatency{0};
 };
 
 class ClientReceiveState {

third-party/thrift/src/thrift/lib/cpp2/async/RocketClientChannel.cpp

@@ -600,8 +600,8 @@ class RocketClientChannel::SingleRequestSingleResponseCallback final
     stats.requestSerializedSizeBytes = requestSerializedSize_;
     stats.requestWireSizeBytes = requestWireSize_;
     stats.requestMetadataAndPayloadSizeBytes = requestMetadataAndPayloadSize_;
-    stats.requestLatency = timeEndSend_ - timeBeginSend_;
-    stats.responseLatency = clock::now() - timeEndSend_;
+    stats.requestWriteLatency = timeEndSend_ - timeBeginSend_;
+    stats.responseRoundTripLatency = clock::now() - timeEndSend_;
     ResponseSerializationHandler handler(protocolId_);
     if (payload.hasException()) {
       if (!payload.exception().with_exception<rocket::RocketException>(

third-party/thrift/src/thrift/lib/cpp2/transport/core/ThriftClientCallback.cpp

@@ -101,8 +101,8 @@ void ThriftClientCallback::onThriftResponse(
   cancelTimeout();
   if (active_) {
     RpcTransportStats stats;
-    stats.requestLatency = timeEndSend_ - timeBeginSend_;
-    stats.responseLatency = clock::now() - timeEndSend_;
+    stats.requestWriteLatency = timeEndSend_ - timeBeginSend_;
+    stats.responseRoundTripLatency = clock::now() - timeEndSend_;
 
     active_ = false;
     auto tHeader = std::make_unique<transport::THeader>();