private async Task<Stream> GetStreamAndWriteStartWrapperIfNecessaryAsync(XmlDictionaryWriter writer, object[] parameters, object returnValue)
{
Stream streamValue = GetStreamValue(parameters, returnValue);
if (streamValue == null)
throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull(_partName);
if (WrapperName != null)
await writer.WriteStartElementAsync(null, WrapperName, WrapperNamespace);
await writer.WriteStartElementAsync(null, PartName, PartNamespace);
return streamValue;
}
