Add get_uuid method to channel

src/core/lib/surface/channel.cc

@@ -217,6 +217,10 @@ char* grpc_channel_get_trace(grpc_channel* channel, bool recursive) {
   return channel->tracer->RenderTrace(recursive);
 }
 
+intptr_t grpc_channel_get_uuid(grpc_channel* channel) {
+  return channel->tracer->GetUuid();
+}
+
 grpc_channel* grpc_channel_create(const char* target,
                                   const grpc_channel_args* input_args,
                                   grpc_channel_stack_type channel_stack_type,

src/core/lib/surface/channel.h

@@ -58,8 +58,14 @@ grpc_mdelem grpc_channel_get_reffed_status_elem(grpc_channel* channel,
 size_t grpc_channel_get_call_size_estimate(grpc_channel* channel);
 void grpc_channel_update_call_size_estimate(grpc_channel* channel, size_t size);
 
+// Returns the JSON formatted channel trace for this channel. If recursive
+// is true, it will render all of the trace for this channel's subchannels.
 char* grpc_channel_get_trace(grpc_channel* channel, bool recursive);
 
+// Returns the channel uuid, which can be used to look up its trace at a
+// later time.
+intptr_t grpc_channel_get_uuid(grpc_channel* channel);
+
 #ifndef NDEBUG
 void grpc_channel_internal_ref(grpc_channel* channel, const char* reason);
 void grpc_channel_internal_unref(grpc_channel* channel, const char* reason);