require "eventmachine"

EM.run do
  1.upto 100  do |i| #this could be database records
    email = EM::Protocols::SmtpClient.send(
      :auth => {:type => :plain, :username => "username@domain.com", :password => ""},
      :domain => "domain.com",
      :host => "smtp.gmail.com",
      :port => 587,
      :starttls => true,
      :from => "sender@example.com",
      :to => ["username@domain.com"],
      :header => { "Subject" => "This is a subject line (#{i})" },
      :body => "#{i}> This is the body of the email")

    email.callback do
      puts "Email sent! for #{i}"
    end

    email.errback do |e|
      puts "Email failed! #{e.inspect}"
    end
  end
end