a System.Reflection.ParameterInfo
The asynchronous design pattern in the common language runtime involves calling a Begin method to start the asynchronous method invocation and an End method to complete the invocation. The Begin method typically returns immediately with an object implementing the IAsyncResult interface, which can then be passed to the End method at a later time to complete the asynchronous method invocation. The returned object implementing the IAsyncResult interface is represented by this property.
For more information on invoking XML Web services asynchronously, see [<topic://cpconInvokingWebServicesAsynchronously>].