/// <summary>
/// Read/write data to/from each easy object.
/// </summary>
/// <param name="runningObjects">
/// The number of <see cref="Easy"/> objects still in process is
/// written by this function to this reference parameter.
/// </param>
/// <returns>
/// A <see cref="CURLMcode"/>, hopefully <c>CURLMcode.CURLM_OK</c>
/// </returns>
/// <exception cref="System.NullReferenceException">
/// This is thrown if the native <c>Multi</c> handle wasn't
/// created successfully.
/// </exception>
public CURLMcode Perform(ref int runningObjects)
{
EnsureHandle();
return(External.curl_multi_perform(m_pMulti,
ref runningObjects));
}