Flight

[Matt Youill]

I've noticed a lot of Flight functionality is hidden in "internal" classes.
What's the reason for this, and is there an alternative?

Specifically, I'd like to add Flight support to an existing HTTP server, 
but it looks like I must use the server that comes with 
arrow::flight::FlightServerBase, or provide my own implementations of 
the internal functions. Is that correct?

Thanks again, Matt