class SetInputBufferPartialSettings

This is the replacement for SetInputBufferSettings().

When the client is using sysmem to allocate buffers, this message is

used instead of SetInputBufferSettings()+AddInputBuffer(). Instead, a

single SetInputBufferPartialSettings() provides the StreamProcessor with

the client-specified input settings and a BufferCollectionToken which

the StreamProcessor will use to convey constraints to sysmem. Both the

client and the StreamProcessor will be informed of the allocated buffers

directly by sysmem via their BufferCollection channel (not via the

StreamProcessor channel).

The client must not QueueInput...() until after sysmem informs the client

that buffer allocation has completed and was successful.

The server should be prepared to see QueueInput...() before the server

has necessarily heard from sysmem that the buffers are allocated - the

server must tolerate either ordering, as the QueueInput...() and

notification of sysmem allocation completion arrive on different

channels, so the client having heard that allocation is complete doesn't

mean the server knows that allocation is complete yet. However, the

server can expect that allocation is in fact complete and can expect to

get the allocation information from sysmem immediately upon requesting

the information from sysmem.