public override object SetHostExecutionContext(HostExecutionContext hostExecutionContext)
        {
            AspNetHostExecutionContext castHostExecutionContext = hostExecutionContext as AspNetHostExecutionContext;

            if (castHostExecutionContext != null)
            {
                // Call base.SetHostExecutionContext before calling our own logic.
                object baseRevertParameter = null;
                if (castHostExecutionContext.BaseContext != null)
                {
                    baseRevertParameter = base.SetHostExecutionContext(castHostExecutionContext.BaseContext);
                }

                ThreadContext currentContext = ThreadContext.Current;
                if (currentContext != null && currentContext.HttpContext.ThreadContextId == castHostExecutionContext.HttpContextThreadContextId)
                {
                    // If we reached this point, then 'castHostExecutionContext' was captured for the HttpContext
                    // that is associated with the ThreadContext that is assigned to the current thread. We can
                    // safely restore it.
                    Action threadContextCleanupAction = currentContext.EnterExecutionContext();

                    // Perform cleanup in the opposite order from initialization.
                    return((RevertAction)(() => {
                        threadContextCleanupAction();
                        if (baseRevertParameter != null)
                        {
                            base.Revert(baseRevertParameter);
                        }
                    }));
                }
                else
                {
                    // If we reached this point, then 'castHostExecutionContext' was captured by us
                    // but is not applicable to the current thread. This can happen if the developer
                    // called ThreadPool.QueueUserWorkItem, for example. We don't restore HttpContext
                    // on such threads since they're not under the control of ASP.NET. In this case,
                    // we have already called base.SetHostExecutionContext, so we just need to return
                    // the result of that function directly to our caller.
                    return(baseRevertParameter);
                }
            }
            else
            {
                // If we reached this point, then 'hostExecutionContext' was generated by our
                // base class instead of by us, so just delegate to the base implementation.
                return(base.SetHostExecutionContext(hostExecutionContext));
            }
        }