private static boolean isSupportedClass(Class<?> clazz) {
        return Observable.class.isAssignableFrom(clazz) ||
               Maybe.class.isAssignableFrom(clazz) ||
               Single.class.isAssignableFrom(clazz) ||
               Completable.class.isAssignableFrom(clazz);
    }
Returns {@code true} if the specified {@link Class} can be handled by the
{@link ObservableResponseConverterFunction}.
rxjava3/src/main/java/com/linecorp/armeria/internal/server/rxjava3/ObservableResponseConverterFunctionProvider.java