Function openthread_sys::otPlatUartFlush

pub unsafe extern "C" fn otPlatUartFlush() -> otError

Flush the outgoing transmit buffer and wait for the data to be sent. This is called when the CLI UART interface has a full buffer but still wishes to send more data.

@retval OT_ERROR_NONE Flush succeeded, we can proceed to write more data to the buffer.

@retval OT_ERROR_NOT_IMPLEMENTED Driver does not support synchronous flush. @retval OT_ERROR_INVALID_STATE Driver has no data to flush.