This should fix the appveyor build.

The previous commit prevents any connections, since the initial presence update is sent while the client is still in the 'connecting' state, rather than the 'connected' state.

This resolves the original issue by preventing a nullref, and the more recent issue by only throwing a detailed exception when the CurrentUser is null (the client isn't logged in).

This prevents a later, less detailed nullref, when attempting to set the CurrentUser's presence data.

This also removes a redundant CurrentUser assignment in the SetGameAsync method, since this will be set later on in the SendStatusAsync method.

Added Jetbrains Rider installing guide

* Update ChannelHelper.cs

* typo

Messages may only be pruned between 0 and 7 days, otherwise a 400 will be thrown.