@Override
  public long getSize() {
    return 1;
  }
Create an instance of {@link IncompleteReadReadableStreamChannel} with an {@code exceptionToThrow}.
@param exceptionToThrow if desired, provide an exception that will thrown on read. Can be null.
ambry-commons/src/test/java/com/github/ambry/commons/ReadableStreamChannelInputStreamTest.java