Acquire stat and hashes in kext to move burden to caller

[droe]

Consider acquiring stat and hashes in-kernel in order to move burden to the task calling exec. This should reduce the amount of time the main thread spends acquiring data the event loop. Requires a separate or shared cache in the kext. Needs extra care when dealing with network file systems, perhaps by delegating acquisition to userspace if path is located on a network file system.

[droe]

Blocked by #6

[droe]

Unblock, as #6 is resolved.