Allows lifetime elision and removes casting

[lucasloisp]

Simple changes guided by clippy

[quadrupleslap]

The "add" looks good but are you sure the elision is equivalent? I put that in their to basically work as a mutex on the capturer.

[lucasloisp]

To be honest I was guided by clippy to make that change. But, as seen on the rustonomicon,

"If there is exactly one input lifetime position (elided or not), that lifetime is assigned to all elided output lifetimes."

fn new(buf: &mut [u8]) -> BufWriter;                    // elided
fn new<'a>(buf: &'a mut [u8]) -> BufWriter<'a>```

[lucasloisp]

What I could try out is removing the 'b annotation on the output to ensure it is the same as the one on the Input (as it was originally)

[owenthewizard]

What's holding this from being merged?