The .Catch() helper currently traces to global trace. This can lead to very noisy trace logs as messages that don't come from any particular trace source end up there, including LOTS of websocket and response FlushAsync errors (due to clients disconnecting).

Let's require a TraceSource to be passed in to Catch(). All call sites will need to flow the current TraceSource for their context in to calls to Catch. This way, the messages only show up if you've configured those TraceSources in the app config.