Efficiently creating a SmallString from std::io::Read

[dwuertz]

I'm looking for an alternative for https://doc.rust-lang.org/std/io/trait.Read.html#method.read_to_string that works with SmallString. So far I haven't found any solutions that doesn't involve additional copies or allocs. I believe an API enhancement is needed somehow. Can you please confirm or otherwise suggest a solution?

I could think of various ways to achieve my goal:

1. Implement std::io::Write for SmallString so I can use std::io::copy().
2. Add SmallString::read<R: Read>(r: &mut R)
3. Add new constructor from_small_vec(data: SmallVec<A>). Since SmallVec already implements std::io::Write, I could use std::io::copy() again. Not as efficient as the others, be cause this would require to move the SmallVec into SmallStringwhich is not free.
4. Add a smallstr::ReadExt trait which is implemented for all T: Read and provides a method read_to_small_str().

I would be willing to work on this myself, but would first appreciate a feedback from the crate's maintainer, which way to favor.