reactor-core/src/main/java/reactor/core/publisher/Hooks.java
public static void onOperatorError(BiFunction<? super Throwable, Object, ? extends Throwable> onOperatorError) {
		onOperatorError(onOperatorError.toString(), onOperatorError);
	}
public static void onOperatorError(BiFunction<? super Throwable, Object, ? extends Throwable> onOperatorError) {
		onOperatorError(onOperatorError.toString(), onOperatorError);
	}
Add a custom error mapping, overriding the default one. Custom mapping can be an
accumulation of several sub-hooks each subsequently added via this method.
<p>
Note that sub-hooks are cumulative, but invoking this method twice with the same
instance (or any instance that has the same `toString`) will result in only a single
instance being applied. See {@link #onOperatorError(String, BiFunction)} for a variant
that allows you to name the sub-hooks (and thus replace them or remove them individually
later on). Can be fully reset via {@link #resetOnOperatorError()}.
<p>
For reference, the default mapping is to unwrap the exception and, if the second
parameter is another exception, to add it to the first as suppressed.

@param onOperatorError an operator error {@link BiFunction} mapper, returning an arbitrary exception
given the failure and optionally some original context (data or error).

@see #onOperatorError(String, BiFunction)
@see #resetOnOperatorError(String)
@see #resetOnOperatorError()