uncheckedThrow(e);
                return null;
            }
        };
    }

    static <T extends Throwable> void uncheckedThrow(Throwable t) throws T {
        throw (T) t; // rely on vacuous cast
    }

    private Model fireEvent(
            Model model,
            ModelBuilderRequest request,
            ModelProblemCollector problems,

     * works well for hash tables since the bin lists tend to be short. (The average length is less
     * than two.)
     *
     * Read operations can thus proceed without locking, but rely on selected uses of volatiles to
     * ensure that completed write operations performed by other threads are noticed. For most
     * purposes, the "count" field, tracking the number of elements, serves as that volatile

    // NOTE: if timeout < 0, remainingNanos will be < 0 and we will fall into the while(true) loop
    // at the bottom and throw a timeoutexception.
    final long timeoutNanos = unit.toNanos(timeout); // we rely on the implicit null check on unit.
    long remainingNanos = timeoutNanos;
    if (Thread.interrupted()) {
      throw new InterruptedException();
    }
    Object localValue = value;

        } else {
            return null;
        }
    }

    @SuppressWarnings("unchecked")
    static <T extends Throwable> void uncheckedThrow(Throwable t) throws T {
        throw (T) t; // rely on vacuous cast
    }

    static class LazyMap<K, V> extends AbstractMap<K, V> {
        private final Supplier<Map<K, V>> supplier;
        private volatile Map<K, V> delegate;