Receive support for Sender Key

Co-authored-by: Fedor Indutny <79877362+indutny-signal@users.noreply.github.com>

ts/util/isByteBufferEmpty.ts

@@ -0,0 +1,10 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { isNumber } from 'lodash';
+
+import { ByteBufferClass } from '../window.d';
+
+export function isByteBufferEmpty(data?: ByteBufferClass): boolean {
+  return !data || !isNumber(data.limit) || data.limit === 0;
+}