Coalesce adjacent stream frames.

gfe-relnote: protected by gfe2_reloadable_flag_quic_coalesce_stream_frames.
PiperOrigin-RevId: 275506579
Change-Id: I94697cc2ceaffc05d03511a342fcf8743780dd77
diff --git a/quic/core/http/quic_spdy_stream.cc b/quic/core/http/quic_spdy_stream.cc
index f90f3c7..c684916 100644
--- a/quic/core/http/quic_spdy_stream.cc
+++ b/quic/core/http/quic_spdy_stream.cc
@@ -310,7 +310,7 @@
   // Write body.
   QUIC_DLOG(INFO) << ENDPOINT << "Stream " << id()
                   << " is writing DATA frame payload of length "
-                  << data.length();
+                  << data.length() << " with fin " << fin;
   WriteOrBufferData(data, fin, nullptr);
 }
 
@@ -1056,7 +1056,7 @@
 
   QUIC_DLOG(INFO) << ENDPOINT << "Stream " << id()
                   << " is writing HEADERS frame payload of length "
-                  << encoded_headers.length();
+                  << encoded_headers.length() << " with fin " << fin;
   WriteOrBufferData(encoded_headers, fin, nullptr);
 
   QuicSpdySession::LogHeaderCompressionRatioHistogram(