code: private Exception checkForResponse() throws NoResponseException {
          switch (state) {
          case Initial:
          case NoResponse:
          case RequestSent:
              throw NoResponseException.newWith(connection, waitFor);
          case Success:
              return null;
          case Failure:
              return getException();
          default:
              throw new AssertionError("Unknown state " + state);
          }
      }
docs: Check for a response and throw a {@link NoResponseException} if there was none.
  <p>
  The exception is thrown, if state is one of 'Initial', 'NoResponse' or 'RequestSent'
  </p>
  @return <code>true</code> if synchronization point was successful, <code>false</code> on failure.
  @throws NoResponseException