Reduce Connection lifetime memory usage

[anrossi]

A number of fields included on QUIC_CONNECTIONs are only used during the handshake. Keeping these values around after the handshake is a waste of memory on the server.
Analyze all these member fields and collect them into their own object which is allocated from a lookaside list and freed once the handshake is complete.

[nibanks]

A thought: Can we have (performance?) tests that measure memory usage?

[anrossi]

On windows, I think we could use ETW to monitor memory usage during a test run and potentially script a tool to analyze the ETW after the test runs.