Perhaps support pattern (meta) properties

[jsccast]

For example,

{"order":"?something","when":"now","#otherProps":false}

might mean that any matching message must have no properties other than order and when. (Presumably such a directive would be local to the structure in which it is present. And presumably not inherited ... )

Or perhaps

{"order":"?something","#expectedTraffic":0.30}

might mean that 30 percent of some traffic should match that pattern. In this case, pattern matching would simply ignore the "#expectedTraffic":0.30, but a tool looking at the pattern would of course still see that data.