When users run find in a single file, we will run regex line by line originally. Now we have a text buffer which stores content in chunks instead of lines, running regex on chunks directly can avoid the overhead of getLineContent.

Things to note while doing this optimization

• When a line sits across Piece Tree nodes/buffers, we fall back to getLineContent then search.
• When users search by multiline regex, we need to get the whole content and then search, like before.
• When users search by single line regex, but the regex contains ^, $ or similar, executing this kind of regex on chunks will miss matches when there are line breaks.