**The `Error` is now an opaque struct**, which allows for more variants to
be added freely, and the internal representation to change without being
breaking changes.
For inspecting an `Error`, there are several `is_*` methods to check for
certain classes of errors, such as `Error::is_parse()`. The `cause` can
also be inspected, like before. This likely seems like a downgrade, but
more inspection can be added as needed!
The `Error` now knows about more states, which gives much more context
around when a certain error occurs. This is also expressed in the
description and `fmt` messages.
**Most places where a user would provide an error to hyper can now pass
any error type** (`E: Into<Box<std::error::Error>>`). This error is passed
back in relevant places, and can be useful for logging. This should make
it much clearer about what error a user should provide to hyper: any it
feels is relevant!
Closes#1128Closes#1130Closes#1431Closes#1338
BREAKING CHANGE: `Error` is no longer an enum to pattern match over, or
to construct. Code will need to be updated accordingly.
For body streams or `Service`s, inference might be unable to determine
what error type you mean to return. Starting in Rust 1.26, you could
just label that as `!` if you never return an error.