*/
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Throwables {
  private Throwables() {}

  /**
   * Throws {@code throwable} if it is an instance of {@code declaredType}. Example usage:
   *
   * <pre>
   * for (Foo foo : foos) {
   *   try {
   *     foo.bar();
   *   } catch (BarException | RuntimeException | Error t) {
   *     failure = t;
   *   }
   * }
   * if (failure != null) {

   *
   * <p>Despite the method name, this method attempts to avoid actually copying the data when it is
   * safe to do so. The exact circumstances under which a copy will or will not be performed are
   * undocumented and subject to change.
   *
   * <p>This method is not type-safe, as it may be called on elements that are not mutually
   * comparable.
   *

         *            sqrtFloor^2 <= x < (sqrtFloor + 1)^2
         * halfSquare - sqrtFloor <= x < halfSquare + sqrtFloor + 1
         * so |x - halfSquare| <= sqrtFloor.  Therefore, it's safe to treat x - halfSquare as a
         * signed long, so lessThanBranchFree is safe for use.
         */
        return sqrtFloor + lessThanBranchFree(halfSquare, x);
    }
    throw new AssertionError();
  }

  /**

      return capture(type);
    }
  }

  /**
   * Wraps around {@code TypeVariable<?>} to ensure that any two type variables are equal as long as
   * they are declared by the same {@link java.lang.reflect.GenericDeclaration} and have the same
   * name, even if their bounds differ.
   *
   * <p>While resolving a type variable from a {@code var -> type} map, we don't care whether the

   * that an abstract method is unimplemented. So instead we use a dynamic proxy to get an
   * implementation. If the method being called on the {@code TypeVariable} instance has the same
   * name as one of the public methods of {@link TypeVariableImpl}, the proxy calls the same method
   * on its instance of {@code TypeVariableImpl}. Otherwise it throws {@link
   * UnsupportedOperationException}; this should only apply to {@code getAnnotatedBounds()}. This

 * {@link #acquire()} blocks if necessary until a permit is available, and then takes it. Once
 * acquired, permits need not be released.
 *
 * <p>{@code RateLimiter} is safe for concurrent use: It will restrict the total rate of calls from
 * all threads. Note, however, that it does not guarantee fairness.
 *

 * instances is using {@link CacheBuilder}.
 *
 * <p>Implementations of this interface are expected to be thread-safe, and can be safely accessed
 * by multiple concurrent threads.
 *
 * <p>When evaluated as a {@link Function}, a cache yields the same result as invoking {@link
 * #getUnchecked}.
 *
 * @param <K> the type of the cache's keys, which are not permitted to be null

        return next;
      }
    }
    return null;
  }

  /**
   * Determines whether two iterables contain equal elements in the same order. More specifically,
   * this method returns {@code true} if {@code iterable1} and {@code iterable2} contain the same
   * number of elements and every element of {@code iterable1} is equal to the corresponding element
   * of {@code iterable2}.
   */

    }
  }

  public static <K, V> ImmutableMap<K, V> copyOf(Map<? extends K, ? extends V> map) {
    if ((map instanceof ImmutableMap) && !(map instanceof ImmutableSortedMap)) {
      @SuppressWarnings("unchecked") // safe since map is not writable
      ImmutableMap<K, V> kvMap = (ImmutableMap<K, V>) map;
      return kvMap;
    } else if (map instanceof EnumMap) {
      EnumMap<?, ?> enumMap = (EnumMap<?, ?>) map;

        /*
         * requireNonNull is safe because the callers promise to put non-null objects in the first
         * `length` array elements.
         */
        @SuppressWarnings("unchecked") // our callers put only E instances into the array
        E onlyElement = (E) requireNonNull(elements[0]);
        return of(onlyElement);
      default:
        /*