This splits the hackney connection pool in three different ones:
- federation (the default for
- media (rich media, media proxy)
- upload (uploader proxy)
- default for the rest (and third-party libs)
Each "part" will stop fighting others ones -- a huge federation outbound could before make the media proxy fail to checkout a connection in time.
splitted media and uploaded media for the good reason than an upload pool will have all connections to the same host (the uploader upstream). it also has a longer default retention period for connections.