private static boolean isComingFromSignedJar(Class<?> type) {
    return type.getSigners() != null;
  }
Returns a {@link TypeCachingLock}, which locks the {@link TypeCache#findOrInsert(ClassLoader, Object, Callable, Object)}.

@param key the key to lock
@return the {@link TypeCachingLock} to use to lock the {@link TypeCache}
spock-core/src/main/java/org/spockframework/mock/runtime/ByteBuddyMockFactory.java