anchor.diff:    --fast-startup
       Produce JavaScript that can be parsed more quickly by VMs. This option
       usually results in larger JavaScript files with faster startup.
  -    Note: the dart:mirrors library is not supported with this option.
   
     --preview-dart-2
       Preview of all Dart 2.0 semantics, this includes generic methods and strong
  -    mode type checks.
  -
  -    This flag is mainly for early dogfooding and will be removed when all
  -    features are shipped.
  +    mode type checks. This will be enabled by default very soon.
   
   The following advanced options can help reduce the size of the generated code,
   but they may cause programs to behave unexpectedly if assumptions are not met.
  
positive.code:   if (enableColors != null) {
      diagnosticHandler.enableColors = enableColors;
    }
    for (String hint in hints) {
      diagnosticHandler.info(hint, api.Diagnostic.HINT);
    }
  
negative.code: 
  Common options:
    -o <file> Generate the output into <file>.
    -m        Generate minified output.
    -h        Display this message (add -v for information about all options).''');
  }
  