When creating asynchronous services, you don't
normally worry about what happens if the service fails to callback
to the parent process. However, if the callback does fails,
it can create major problems for the parent process, making it
stall without an easy way to recover.
Take, for example, the following process, called
SubmitCreditCheck. The asynchronous Call: Perform Credit Check
service blocks until the Receive: Perform Credit Check callback
message is received. If, for...
