Some docs say for event notifications to use SignalR, while others say a matchmaking sdk completely separate from the client sdk. For example, if we look at the latest + greatest matchmaking doc:
According to this doc, I can either poll every 6s (not ideal) or... no mention of signalr, but the Multiplayer SDK (separate from client sdk) with a link:
...but this link calls it the Matchmaking Client SDK, NOT the Multiplayer SDK.
Scrolling down jumps back to calling it a Multiplayer SDK and says to download it here:
...which only has the same Game SDK, which is also called the Client SDK, and apparently also called the Multiplayer SDK AND the Matchmaking SDK;
If you dive into the rabbit hole even further, you'll find recommendations to use the OSS with links that eventually (and unexpectedly) revolve back to the same links above, all frustratingly using different keywords of which SDK/APIs to use).
What a wild goose chase of confusion! Please:
What is the difference between these 4 SDKs?
For Unreal users, what is "the" turn-to for matchmaking events so we don't have to poll that's allegedly built-in?
Another link randomly leads to OSS, which is neither signalR OR
For other Googlers, here are some facts discovered along my journey:
The "Matchmaker" API is obsolete and broken (since early 2021 without letting users know).
The "Client/Matchmaking" API is also obsolete and broken (since early 2021 without letting users know).
The "Multiplayer/Matchmaking" API is the one to use for non-events, but for some reason (and confusingly), does not contain callback events -- unlike the deprecated APIs (hinting that this API may actually be a 2-year-old beta that no one seems to have updated).
There is some OSS implementation somewhere, but the docs about OSS all seem to vaguely loop back to the list of SDKs (where only 1 is listed for Unreal).