Timed sends currently not supported

[gth828r]

From what I can tell, it looks like timed sends (i.e., tell the USRP to transmit at timepoint T) is not supported through this crate. It would be nice to have support for this feature.

[gth828r]

Based on what I can tell, I think this is just a matter of having the TransmitStreamer transmit function take in TransmitMetadata.

Right now, the TransmitMetadata is treated as an output value which is initialized to the default value at the beginning of the function. It might be sufficient to take in an Optional<TransmitMetadata>> argument and use the default value if no metadata is provided. It might also make sense to sanity check the provided TransmitMetadata since it gets passed into unsafe code, but I am not sure what that entails off the top of my head.

[samcrow]

I don't have any hardware to test with right now, but that sounds promising.