DirExists checks if dirPath is an actual directory in the local file system.

EnsureDir recursevily creates a directory tree if it doesn't exist already.

FileExists checks if filePath is an actual file in the local file system.

startSignalWatcher spins off a thread monitoring termination signals and retuns a function that returns whether termination was requested.

stopSignalWatcher sends a fake signal to the monitoring thread making it terminate.

ShouldAbortFunction is a function that determines whether early termination was requested by the user.