prints function Null safety
- dynamic matcher
Matches a Function that prints text that matches
matcher may be a String or a Matcher.
If the function this runs against returns a Future, all text printed by the function (using Zone scoping) until that Future completes is matched.
This only tracks text printed using the print function.
This returns an
AsyncMatcher, so expect won't complete until the matched
Matcher prints(matcher) => _Prints(wrapMatcher(matcher));