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: serialized_execution.rb
    path of file: ./repos/concurrent-ruby/lib/concurrent-ruby/concurrent/executor
    
    the code of the file until where you have to start completion: require 'concurrent/errors'
require 'concurr
    
    def work(job)
      job.call
    ensure
      synchronize do
        job = @stash.shift || (@being_executed = false)
      end

      # TODO maybe be able to tell caching pool to just enqueue this job, because the current one end at the end
      # of this block
      call_job job if job
    end