NewCJLock Create a new ConcurrentJob Lock Middleware.

NewTagHandlerMW Create a new Tag Handler Middleware.

ConcurrentJobBlocker is a Middleware that will defer a job if one is already running.

HasTagHandler is a Middleware that will Defer jobs if the Requirements are not meet Requirements are Specified as "Tags" (strings) and a Job has a list of Tags needed When a Job is about to be dispatched, the Jobs "Required" tags are compared against a list of "available" tags, and if the available tags does not match the required tags, the job is deferred (or canceled if there is no other Middleware after this one.).