code: func NewCacheKey(ctx fab.ClientContext, pvdr Provider, channelID string) (CacheKey, error) {
  	return &cacheKey{
  		key:       channelID,
  		channelID: channelID,
  		context:   ctx,
  		pvdr:      pvdr,
  	}, nil
  }
docs: // NewCacheKey returns a new CacheKey