linesToConsume property
The lines from _start to _pos (inclusive), it works as a buffer for
some blocks, for example:
When the ParagraphSyntax parsing process is interrupted by the
SetextHeaderSyntax, so this structure is not a paragraph but a setext
heading, then the ParagraphSyntax.parse does not have to retreat the
reading position, it only needs to return null, the SetextHeaderSyntax
will pick up the lines in linesToConsume.
Implementation
List<Line> get linesToConsume => lines.getRange(_start, _pos + 1).toList();