Harlequinn is a real-time networking library primarily aimed at games. It is based on the Quinn implementation of the QUIC protocol.
Harlequinn wraps around Quinn to provide an API that can be easily used from a synchronous game loop. It also implements some additional nice-to-have features out of the box.
A lot of features provided by Harlequinn are implemented as part of the QUIC implementation by Quinn. For convenience notable features implemented by Quinn are listed here as well.