public void ifPresent(Consumer<? super T> consumer) {
        if (value != null)
            consumer.accept(value);
    }
If a value is present, invoke the specified consumer with the value,
otherwise do nothing.

@param consumer block to be executed if a value is present
@throws NullPointerException if value is present and {@code consumer} is
                             null
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/util/Optional.java