code: public static Set<Bugsnag> uncaughtExceptionClients() {
          UncaughtExceptionHandler handler = Thread.getDefaultUncaughtExceptionHandler();
          if (handler instanceof ExceptionHandler) {
              ExceptionHandler bugsnagHandler = (ExceptionHandler) handler;
              return Collections.unmodifiableSet(bugsnagHandler.uncaughtExceptionClients());
          }
          return Collections.emptySet();
      }
docs: Retrieves all instances of {@link Bugsnag} which are registered to
  catch uncaught exceptions.
  
  @return clients which catch uncaught exceptions