If will run the cleanup function if the bool value is true.

IfNot will run the cleanup function if the bool value is false.

IfNotPred will run the cleanup function if pred returns false.

IfPred will run the cleanup function if pred returns true.

IgnoreError silently ignores errors in the cleanup function.

WithError returns a cleanup function calling a custom handler if an error occured.

FailClean keeps track of functions to be executed of FailClean did not receive a success signal.