From 375441721d0c44fd8c1b5b809cfb4b5ca0dac126 Mon Sep 17 00:00:00 2001
From: OISHI Masakuni <yamasa@bsdhouse.org>
Date: Sun, 31 Jul 2022 15:22:09 +0900
Subject: [PATCH] Launch SendMessage coroutine with
 `CoroutineStart.UNDISPATCHED`.

Especially, this improves performance when the current dispatcher is `Dispatchers.Main`.
---
 stub/src/main/java/io/grpc/kotlin/ClientCalls.kt | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/stub/src/main/java/io/grpc/kotlin/ClientCalls.kt b/stub/src/main/java/io/grpc/kotlin/ClientCalls.kt
index 3dce6967..3c07e47c 100644
--- a/stub/src/main/java/io/grpc/kotlin/ClientCalls.kt
+++ b/stub/src/main/java/io/grpc/kotlin/ClientCalls.kt
@@ -22,13 +22,13 @@ import io.grpc.MethodDescriptor
 import io.grpc.Status
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineName
+import kotlinx.coroutines.CoroutineStart
 import kotlinx.coroutines.NonCancellable
 import kotlinx.coroutines.cancel
 import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.channels.onFailure
 import kotlinx.coroutines.coroutineScope
 import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -309,7 +309,10 @@ object ClientCalls {
         headers.copy()
       )
 
-      val sender = launch(CoroutineName("SendMessage worker for ${method.fullMethodName}")) {
+      val sender = launch(
+        context = CoroutineName("SendMessage worker for ${method.fullMethodName}"),
+        start = CoroutineStart.UNDISPATCHED
+      ) {
         try {
           request.sendTo(clientCall, readiness)
           clientCall.halfClose()