releaseLock() {
    if (!this.ownerReadableStream) {
      return;
    }
    if (this.readRequests.length) {
      throw new TypeError(
          'Cannot release a readable stream reader when it still has ' +
          'outstanding read() calls that have not yet settled');
    }
    this.release();
  }
Release the lock on the stream. Any further calls to read() will error,
and the stream can create another reader.
https://streams.spec.whatwg.org/#default-reader-release-lock
@return {void}
@override