Currently, all FreeRDP-based clients don't send any WaveConfirm PDUs
for received samples, when using a dynamic channel for audio output
redirection.
[MS-RDPEA] 2.2.3.8 Wave Confirm PDU mentions, that a WaveConfirm PDU
MUST be sent, when a WaveInfo PDU + Wave PDU, or Wave2 PDU is received
and when the audio data sample is emitted to completion by the client.
The first WaveConfirm PDU is used by the server to determine the
network latency and the second WaveConfirm PDU is used by the server to
determine the render latency.
So, fix the current behaviour, where FreeRDP currently does not send
any WaveConfirm PDU, when using the dynamic channel, or only sends one
WaveConfirm PDU for the sample.
For the first WaveConfirm PDU, use the same timestamp, that was
included in the first WaveInfo/Wave2 PDU.
For the second WaveConfirm PDU, add the render latency on top of the
arrival timestamp.
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