Playback only: minimum request. The server does not request less than minreq bytes from the client, instead waits until the buffer is free enough to request more bytes at once. It is recommended to set this to (uint32_t) -1, which will initialize this to a value that is deemed sensible by the server. This should be set to a value that gives PulseAudio enough time to move the data from the per-stream playback buffer into the hardware playback buffer.
Referenced by pa_stream_set_buffer_attr().