anchor.diff:  
   |`vertxVersion`
   |the Vert.x version to use
  -|"3.4.2"
  +|`"3.4.2"`
   
   |`launcher`
   |the main class name
  
positive.code: 
  |`mainVerticle`
  |the main verticle, when using `io.vertx.core.Launcher` as `launcher`
  | ""
  
  |`args`
  |a list of command-line arguments to pass
  
negative.code: 
  |`config`
  |either a file or direct JSON data to provide configuration
  |`""`
  
  |`workDirectory`
  |the working directory
  