Allows masking of interrupt flag if previously the flag is already set. Does nothing otherwise. Typical use:

InterruptUtil interruptUtil = new InterruptUtil(context);

try {
    interruptUtil.maskInterruptFlag();
    someOtherThread.join(delay);
} catch (InterruptedException e) {
    // reachable only if join does not succeed within delay.
    // Without the maskInterruptFlag() call, the join() would have returned
    // immediately
    // had the current thread been interrupted previously, i.e. before entering
    // the above block
} finally {
    interruptUtil.unmaskInterruptFlag();
}