Implements the same API as the "Request" objects created by
Continuity::Adapt::HttpDaemon and other adapters. These faked request objects
go over the request queue but instead of containing a request from a user,
they contain a request from another part of the system.
Use Continuity::Mapper instead.
Call with the code to run in another coroutine's execution context. The
execution context includes the call stack, including all of the data returned
by Carp::confess, Padwalker, caller, and so on.
One Inspector instance can be reused but can only on one context
at a time or else the locking stuff will probably go all breaky.
It's a bit silly that this is here but having it here helps with locking.
Continuity::Mapper has a bit nicer interface to the same thing.