From 9558618182aa817ad5aa9885f1fe12003ee1a93e Mon Sep 17 00:00:00 2001
From: Muxi Yan <mxyan@google.com>
Date: Tue, 6 Nov 2018 11:37:41 -0800
Subject: [PATCH] Check if call is cancelled

---
 src/objective-c/GRPCClient/GRPCCall.m | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/objective-c/GRPCClient/GRPCCall.m b/src/objective-c/GRPCClient/GRPCCall.m
index 5ce361300d6..1338c1edd60 100644
--- a/src/objective-c/GRPCClient/GRPCCall.m
+++ b/src/objective-c/GRPCClient/GRPCCall.m
@@ -237,7 +237,9 @@ const char *kCFStreamVarName = "grpc_cfstream";
 
 - (void)writeData:(NSData *)data {
   dispatch_async(_dispatchQueue, ^{
-    [self->_pipe writeValue:data];
+    if (self->_call) {
+      [self->_pipe writeValue:data];
+    }
   });
 }