Remove use of sprintf
diff --git a/src/core/transport/chttp2_transport.c b/src/core/transport/chttp2_transport.c
index 17b37d6..c273dd7 100644
--- a/src/core/transport/chttp2_transport.c
+++ b/src/core/transport/chttp2_transport.c
@@ -1015,7 +1015,7 @@
       s->cancelled = 1;
       stream_list_join(t, s, CANCELLED);
 
-      sprintf(buffer, "%d", local_status);
+      gpr_ltoa(local_status, buffer);
       grpc_sopb_add_metadata(
           &s->parser.incoming_sopb,
           grpc_mdelem_from_strings(t->metadata_context, "grpc-status", buffer));