class Parallel::Worker

def close_pipes

when running in isolation mode, so we have to check if it is closed before closing
might be passed to started_processes and simultaneously closed by another thread 
def close_pipes
  read.close unless read.closed?
  write.close unless write.closed?
end

def initialize(read, write, pid) 

def initialize(read, write, pid)
  @read = read
  @write = write
  @pid = pid
end

def stop 

def stop
  close_pipes
  wait # if it goes zombie, rather wait here to be able to debug
end

def wait 

def wait
  Process.wait(pid)
rescue Interrupt
  # process died
end

def work(data) 

def work(data)
  begin
    Marshal.dump(data, write)
  rescue Errno::EPIPE
    raise DeadWorker
  end
  result = begin
    Marshal.load(read)
  rescue EOFError
    raise DeadWorker
  end
  raise result.exception if result.is_a?(ExceptionWrapper)
  result
end