Use the UNKNOWN message filter to flush the bus
Use the UNKNOWN message filter to flush the bus

The unknown or none message type is not a valid polling filter,
instead we interpret it as a flushing request. As such we flush
the bus for "timeout" nanoseconds

RidgeRun/gstd-1.x,RidgeRun/gstd-1.x,RidgeRun/gstd-1.x,RidgeRun/gstd-1.x