The intent was to run custom code after the user is done modifying the socket,
for example to update a (not yet existing) port->socket map in SocketSet. However
this wouldn't work, since the SocketRef would have to borrow the SocketSet at
the same time as the Socket to be able to notify the SocketSet.
I believe such indexing can be achieved by setting a "dirty" bit *before* giving
the socket to the user, then on poll() reindexing all dirty sockets. This could
even be faster: if user gets a socket multiple times between polls, it'd be reindexed
only once.
These were flagged by `cargo clippy`:
warning: redundant field names in struct initialization
There are plenty more redundant field names, but I only changed the ones
where the initialization was a single line of code. I still prefer the
redundant style for multi-line initializations (and I'm under the
impression that others agree), so I've also disabled the warning.
This paves way for adding more metadata apart from handles,
such as caches and so on.
This commit also removes SocketHandle::EMPTY in favor of
SocketHandle::default() since they are functionally identical.
This is basically a rename that now calls an apple an apple,
except user code can no longer change it. It's not obvious if
user code getting the socket handle from the socket is very useful,
but it's not harmful either, so why not.
I haven't realized that a feature `log` with an optional crate
dependency `log` activates that dependency, and added the prefix
to avoid a "clash". This is unnecessary.