anchor.diff:  requiring a login.
   
   The login will currently use DIGEST-MD5, CRAM-MD5, PLAIN and LOGIN in order of
  -preference, if the server announces AUTH but you don't need it (e.g. if you are
  -authenticated by a local ip address) turn login off with `LoginOption.DISABLE`
  -To specifically select a AUTH method or define the order of preference, you
  +preference. If the server announces AUTH but you don't need it (e.g. if you are
  +authenticated by a local ip address) turn login off with `LoginOption.DISABLE`.
  +To specifically select an AUTH method or define the order of preference, you
   can do `setAuthMethods("METHOD1 METHOD2")`.
   
   == link:src/main/java/io/vertx/example/mail/MailServiceExample.java[MailServiceExample]
  
positive.code: 
  == link:src/main/java/io/vertx/example/mail/MailImages.java[MailImages]
  
  This example shows how to send inlined images in mails.
negative.code: This example shows how to leave out the From address in a mail but setting
  the bounceAddress property instead.
  
  the example deploys the mail service, however you can refactor the example to
  skip this step and start the service as follows:
  
  ----
  vertx run service:io.vertx.mail-service
  