code: @Nonnull
    public CloseableHttpResponse execute (@Nonnull final HttpUriRequest aRequest) throws IOException
    {
      return execute (aRequest, (HttpContext) null);
    }
docs: Execute the provided request without any special context. Caller is
  responsible for consuming the response correctly!
  
  @param aRequest
  The request to be executed. May not be <code>null</code>.
  @return The response to be evaluated. Never <code>null</code>.
  @throws IOException
  In case of error
  @throws IllegalStateException
  If this manager was already closed!