allMatches method Null safety
Matches this pattern against the string repeatedly.
start is provided, matching will start at that index.
The returned iterable lazily finds non-overlapping matches
of the pattern in the
If a user only requests the first match,
this function should not compute all possible matches.
The matches are found by repeatedly finding the first match
of the pattern in the string, initially starting from
and then from the end of the previous match (but always
at least one position later than the start of the previous
match, in case the patter matches an empty substring).
Iterable<Match> allMatches(String string, [int start = 0]);