GHSA-w3g5-2848-2v8r

The `Generator` type is an iterable which uses a generator function that yields values. In affected versions of the crate, the provided function yielding values had no `Send` bounds despite the `Generator` itself implementing `Send`. The generator function lacking a `Send` bound means that types that are dangerous to send across threads such as `Rc` could be sent as part of a generator, potentially leading to data races. This flaw was fixed in commit [`f7d120a3b`](https://github.com/Xudong-Huang/generator-rs/commit/f7d120a3b724d06a7b623d0a4306acf8f78cb4f0) by enforcing that the generator function be bound by `Send`.