AsyncInterceptor Forking Execution and Racing

[FGS-BMarkham]

I'm running into a situation where sometimes when execution passes through an async interceptor, execution splits into two threads of execution, which then race each other.

I've noticed that d84db87 introduces quite a bit of complication to async interceptors, which may be responsible for this bug, but I don't know enough about the original motivation of that change in order to surmise how the bug was introduced. From reading d84db87, it very much looks like the split execution is intentional, but that doesn't make much sense to me.

Help would be appreciated.

[FGS-BMarkham]

If I roll my own version of AsyncInterceptor in which the tasks started by Task.Factory.StartNew(…) have .Wait() called on them after all the continuations are defined, my interceptors stop racing, which is good.

Unfortunately, the thread pool usage in this class still seems non-ideal (due to that being a rather limited resource in something like a web application), but I was unable to come up with a better overall design for the implementation of AsyncInterceptor.