default <V> MapperFunction<T, V> and(MapperFunction<? super R, ? extends V> after) {
            return in -> {
                final R out = apply(in);
                if (out != null) {
                    return after.apply(out);
                } else {
                    // Stop chaining
                    return null;
                }
            };
        }
Creates a new {@link MapperFunction} from the specified {@link Predicate}.
core/src/main/java/com/linecorp/armeria/common/stream/FuseableStreamMessage.java