Pass an owned value to log's methods?

Hi @KodrAus @Thomasdezeeuw,

According to the following code:

https://github.com/rust-lang/log/blob/6e1735597bb21c5d979a077395df85e1d633e077/src/__private_api.rs#L81

https://github.com/rust-lang/log/blob/6e1735597bb21c5d979a077395df85e1d633e077/src/__private_api.rs#L103-L105

Given that Record<'a> and Metadata<'a> already conatins all refs in their fields, and we have an owned value at the caller side, I'd like to know why we pass a ref &Record and &Metadata instead of Record<'a> and Metadata<'a>, to the log and enabled method.

I mean, is it possible to change (despite it's a breaking change, just think of it technically):

pub trait Log: Sync + Send {
    fn enabled(&self, metadata: &Metadata) -> bool;
    fn log(&self, record: &Record);
    fn flush(&self);
}

into

pub trait Log: Sync + Send {
    fn enabled(&self, metadata: Metadata<'_>) -> bool;
    fn log(&self, record: Record<'_>);
    fn flush(&self);
}

Any downside?

Start with src/__private_api.rs at the linked lines and review the Log trait signatures for enabled and log. Trace how Record and Metadata are passed from the caller, then document the compatibility and ownership implications of changing those parameters; done means reaching a justified API decision.