Function set_log_event_hook 

pub fn set_log_event_hook(hook: LogEventHook) -> Result<(), LogEventHook>

Register a global log sink hook. Prefer add_log_event_hook when multiple sinks may coexist. Returns Err(hook) only if an older single-hook API path reserved the slot — with the multi-hook registry this always succeeds via add_log_event_hook.