Add comments about the fix

src/core/ext/transport/chttp2/client/chttp2_connector.cc

@@ -216,6 +216,12 @@ static void chttp2_connector_connect(grpc_connector* con,
   grpc_closure* closure = &c->connected;
   grpc_endpoint** ep = &c->endpoint;
   gpr_mu_unlock(&c->mu);
+  // In some implementations, the closure can be flushed before
+  // grpc_tcp_client_connect and since the closure requires access to c->mu,
+  // this can result in a deadlock. Refer
+  // https://github.com/grpc/grpc/issues/16427
+  // grpc_tcp_client_connect would fill c->endpoint with proper contents and we
+  // make sure that we would still exist at that point by taking a ref.
   grpc_tcp_client_connect(closure, ep, args->interested_parties,
                           args->channel_args, &addr, args->deadline);
 }