log: allow external definition of log handling (#1561)

* poc

* linter: fix

---------

Co-authored-by: Ryan O'Hara-Reid <ryan.oharareid@thrasher.io>

log/custom_log_hooks.go

@@ -0,0 +1,17 @@
+package log
+
+// CustomLogHook is a function type for external log handling. It should return
+// true if the library's internal logging system should be bypassed, or false
+// if the library's internal logging system should be used.
+type CustomLogHook func(header, subLoggerName string, a ...any) (bypassLibraryLogSystem bool)
+
+var customLogHook CustomLogHook
+
+// SetCustomLogHook sets a custom log hook function that allows the complete
+// bypass of the library's internal logging system. This is useful for
+// implementing custom log handling.
+func SetCustomLogHook(h CustomLogHook) {
+	mu.Lock()
+	customLogHook = h
+	mu.Unlock()
+}