Merge pull request #452 from ctiller/fix

Add some documentation
diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index 37ae426..ee8e858 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -404,7 +404,11 @@
       return;
     }
   }
-  out.recv_status.set_value(GRPC_STATUS_UNKNOWN, out.recv_status.user_data);
+  if (call->is_client) {
+    out.recv_status.set_value(GRPC_STATUS_UNKNOWN, out.recv_status.user_data);
+  } else {
+    out.recv_status.set_value(GRPC_STATUS_OK, out.recv_status.user_data);
+  }
 }
 
 static void get_final_details(grpc_call *call, grpc_ioreq_data out) {