docs: public long keyOf(final Object value) {
  	final long[] foundKey = new long[1];
  	boolean notFound = forEachPair(
  		new LongObjectProcedure() {
  			public boolean apply(long iterKey, Object iterValue) {
  				boolean found = value == iterValue;
  				if (found) foundKey[0] = iterKey;
  				return !found;
  			}
  		}
  	);
  	if (notFound) return Long.MIN_VALUE;
  	return foundKey[0];
  }