Trying to run this example currently fails:

require 'em/pure_ruby'
module EchoServer
  def receive_data(data)
    send_data(data)
  end
end

EventMachine::run{
  EventMachine::start_server "0.0.0.0", 8081, EchoServer
}


This results in:

NoMethodError: undefined method `run' for EventMachine:Module