class Net::SSH::Connection::SingleSessionEventLoop

optimized version for a single session

def ev_preprocess(&block)

we call block with session as argument
Compatibility for original single session event loops: 
def ev_preprocess(&block)
  return false if block_given? && !yield(@sessions.first)
  @sessions.each(&:ev_preprocess)
  return false if block_given? && !yield(@sessions.first)
  return true
end

def ev_select_and_postprocess(wait) 

def ev_select_and_postprocess(wait)
  raise "Only one session expected" unless @sessions.count == 1
  session = @sessions.first
  sr, sw, actwait = session.ev_do_calculate_rw_wait(wait)
  readers, writers, = IO.select(sr, sw, nil, actwait)
  session.ev_do_handle_events(readers, writers)
  session.ev_do_postprocess(!((readers.nil? || readers.empty?) && (writers.nil? || writers.empty?)))
end