Add option to index only first N bytes of extracted text

Arguably files like word documents, XLS files, PPT, PDFs are by nature "rich" in useful and relevant words in the first portions of them. If we only indexed the first portions of text of those documents we would still end up with useful additions to the search index like:

• Documents: title, author, tables of contents
• Presentations: title, agenda, etc.
• Spreadsheets or data files: column names

So, I'm wondering if the options a /admin/config/search/search-api/index/[index-name]/processors could have an option to truncate the extracted text to a certain size. This is the content that would make it into both the index and would be cached locally.