* returns <tt>Long.MIN_VALUE</tt> if no such key exists.
*/
public long keyOf(final int value) {
final long[] foundKey = new long[1];
boolean notFound = forEachPair(
new LongIntProcedure() {
public boolean apply(long iterKey, int iterValue) {
boolean found = value == iterValue;
if (found) foundKey[0] = iterKey;
return !found;
}