@Override
  public int available() {
    return currentChunk == null ? 0 : currentChunk.remaining();
  }
Create a ReadableStreamChannelInputStream with the given {@link ReadableStreamChannel}.
@param readableStreamChannel the {@link ReadableStreamChannel} that needs to be converted into an
{@link InputStream}.
ambry-commons/src/main/java/com/github/ambry/commons/ReadableStreamChannelInputStream.java