Lazy logging errors to bost performace

lazy-logger.rb

# Meassure the difference:
#  $ ab -r -n 10 http://127.0.0.1:4567/  | grep "Requests per second"
require 'sinatra'
require 'logger'

ERRLOG = Logger.new "#{__FILE__}.err"
ERRQ = Queue.new

Thread.new do
  loop do
    while msg = ERRQ.pop do
      ERRLOG.error msg
    end
    sleep 2
  end
end

disable :logging

get '/' do
  ERRQ << "That thing happened again"
  send_file __FILE__, disposition: 'inline'
end