code: func (cp *ChannelProvider) CloseContext(ctx fab.ClientContext) {
  	key, err := newCtxtCacheKey(ctx)
  	if err != nil {
  		logger.Warnf("Unable to close context: %s", err)
  		return
  	}
  	logger.Warnf("Deleting context cache...")
  	cp.ctxtCaches.Delete(key)
  }
docs: // CloseContext frees resources and caches for the given context.