reactor-core/src/main/java/reactor/core/scheduler/Schedulers.java
public static void onHandleError(BiConsumer<Thread, ? super Throwable> c) {
		if (log.isDebugEnabled()) {
			log.debug("Hooking new default: onHandleError");
		}
		onHandleErrorHook = Objects.requireNonNull(c, "onHandleError");
	}
public static void onHandleError(BiConsumer<Thread, ? super Throwable> c) {
		if (log.isDebugEnabled()) {
			log.debug("Hooking new default: onHandleError");
		}
		onHandleErrorHook = Objects.requireNonNull(c, "onHandleError");
	}
Define a hook that is executed when a {@link Scheduler} has
{@link #handleError(Throwable) handled an error}. Note that it is executed after
the error has been passed to the thread uncaughtErrorHandler, which is not the
case when a fatal error occurs (see {@link Exceptions#throwIfJvmFatal(Throwable)}).

@param c the new hook to set.