perf: back more extracted String instances by the original input

[jbee]

String#substring creates a "view" onto the original string backed by the same byte[]. It would be nice if more of the extracted strings could just be views backed by the original full input.

The difficulty is that String internally uses byte[] not char[] (any longer). Also it is not possible to wrap an existing char[] or byte[] into a String instance without copying it entirely or a section of it. This means most likely sharing can only be done by changing from String to CharSequence in the places that expose shared content.