You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: unfollow_buffer.rb
    path of file: ./repos/kitsu-server/lib/buffered_stream_client
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

class BufferedStreamClient
  class UnfollowBuffer < RedisBuffer
    # The numb
    
    def flush_batch
      # TODO: switch to unfollow-many
      unfollows = next_batch_for(size: RATE_LIMIT)
      return if unfollows.blank?
      begin
        unfollows.each do |unfollow|
          source = unfollow['source'].split(':')
          target = unfollow['target'].split(':')
          feed = StreamRails.client.feed(*source)
          feed.unfollow(*target, unfollow['keep_history'])
        end
      rescue StandardError
        return_batch_to(unfollows, group: 'default')
        raise
      end