Informs .NET/Link that your code will be manually sending a result back to Mathematica.
This circumvents the normal automatic return to Mathematica of whatever the method being called returns.
This method is usable only in .NET code that is invoked in a call from Mathematica, as described in Part 1 of the .NET/Link User Guide. In other words, it is only used in code that is called from a Mathematica session via the "installable .NET" mechanism. Programmers who are launching the kernel and controlling it from a .NET program will have no use for this method.The IKernelLink object on which this method will be called will probably be obtained via the StdLink.Link property.
The name "BeginManual" was chosen instead of, say, "SetManual" to emphasize that the link enters a special mode the moment this method is called. To allow the most graceful exception handling, you should delay calling BeginManual until right before you begin to write the result on the link.