public Guarded enter() {
		if (inGuarded) {
			violation = violated(true, violation);
			return null;
		}
		inGuarded = true;
		violation = null;
		return guarded;
	}
Notify the guard of entry into the guarded block

<p>
This should always be used in a {@code try-with-resources} block. This will ensure that the
guard is notified of exit from the guarded block, even in exceptional circumstances.

<p>
NOTE: Re-entering the guarded portion is itself a violation.

@return a closeable for notifying the guard of exit from the guarded block, or null if
        reentering the guarded block
Ghidra/Framework/Generic/src/main/java/generic/concurrent/ReentryGuard.java