Pulling the original same and size of the downloading file

How can I get the original file name?
I'm creating download manager and it's not possible to set the name of every file manually so is there a way to pull the original file name and size through the link itself knowing that it won't be the same link structure everytime

The issue names no files, tests, or entry points. Start by locating the download task handling in the Flutter plugin and determine how arbitrary links expose the original filename and size; done means the supported behavior and its platform-specific limits are documented or covered by verification.

Written by the indexing model from the issue text.