Consider a better error abstraction for the Handler trait

[reem]

IoResult is generally pretty limiting, and this just encourages tons of "OtherIoError" instead of building meaningful abstractions. I am biased to recommend https://github.com/reem/rust-error.git

EDIT: Upon further thought, I think that such a complex error abstraction might be inappropriate, what you really want is Result<(), Box<Show>> because all you are doing is showing the type. This also allows downstream users maximum flexibility. You will, unfortunately, have to write a small hack to get around the lack of impl Show for Box<Show>.