code: @Override
    public void removeNamespace(final MongoNamespace namespace) {
      this.instanceLock.writeLock().lock();
      try {
        if (!this.nsStreamers.containsKey(namespace)) {
          return;
        }
        final NamespaceChangeStreamListener streamer = this.nsStreamers.get(namespace);
        streamer.stop();
        this.nsStreamers.remove(namespace);
      } finally {
        this.instanceLock.writeLock().unlock();
      }
    }
docs: Requests that the given namespace stopped being listened to for change events.
  
  @param namespace the namespace to stop listening for change events on.