Evaluate the use of `warn!` and `error!` logging in `radicle-fetch`.
The majority are downgraded to `debug!`, the rest either being
downgraded to `info!` or removed altogether.
The message that is returned by `gix-transport` for I/O errors can be
unhelpful, since it does not provide the reason for what happened.
Instead, surface the error so that it provides more detail for logging.
Allow the fetch interface to accept anything that implements
`AsRef<Repository>`. This allows flexibility in the types that the `Handle` can
accept.
This change is motivated by wanting to introduce a type that is a temporary
repository that wraps a `Repository`.
The interface of the `Handle` has two methods: `Handle::repository` and
`Handle::repository_mut`. However, the calling logic would always access the
`Handle::repo` field.
This is cleaned up by making this field private, and using the
`Handle::repository` method instead. There were no calls to `repository_mut`,
and so the method was removed.
The `fn io_other` disguises all sorts of errors as I/O errors, making
errors in the transport component of `radicle-fetch` harder to
understand.
Instead, expose a new error type that allows to discriminate.
Fintan Halpenny
Lorenz Leutgeb