Fired at the beginning of the check routine that checks to see if the request has failed. This is your hook to override the default failure behavior.

This method implementation should do the following:

• Return true or false based on matching
• Call SetErrror on the passed WebMonitorSite instance if an error occurred

Note unlike most other events this events result overrides the base checking mechanism. Returning true means that the request is to succeed, false means the request is to fail. No further comparison code runs after this event is implemented. In other words, it completely overrides the default event checking.