reactor-core/src/main/java/reactor/core/publisher/Operators.java
public static <T> void onNextDropped(T t, Context context) {
		Objects.requireNonNull(t, "onNext");
		Objects.requireNonNull(context, "context");
		Consumer<Object> hook = context.getOrDefault(Hooks.KEY_ON_NEXT_DROPPED, null);
		if (hook == null) {
			hook = Hooks.onNextDroppedHook;
		}
		if (hook != null) {
			hook.accept(t);
		}
		else if (log.isDebugEnabled()) {
			log.debug("onNextDropped: " + t);
		}
	}
public static <T> void onNextDropped(T t, Context context) {
		Objects.requireNonNull(t, "onNext");
		Objects.requireNonNull(context, "context");
		Consumer<Object> hook = context.getOrDefault(Hooks.KEY_ON_NEXT_DROPPED, null);
		if (hook == null) {
			hook = Hooks.onNextDroppedHook;
		}
		if (hook != null) {
			hook.accept(t);
		}
		else if (log.isDebugEnabled()) {
			log.debug("onNextDropped: " + t);
		}
	}
An unexpected event is about to be dropped.
<p>
If no hook is registered for {@link Hooks#onNextDropped(Consumer)}, the dropped
element is just logged at DEBUG level.

@param <T> the dropped value type
@param t the dropped data
@param context a context that might hold a local next consumer