We don't have any `Result`s to propagate in this function, so the
`Result` return wrapper is unnecessary.

Must have copied this signature from Civet without thinking:
https://github.com/conduit-rust/rust-civet/blob/ab9c52ca634f65439060c2248295d2ac354aead5/src/lib.rs#L214

Since we don't need to add any additional context or messages here, we
can turn off error context for these variants and shorten error
propagation.

Write doc comments for functions and types, and include a short example.

Reduce a few lines.

Provide a mechanism to get detailed error messages when 500 internal
server errors happen.

We don't want to expose any detailed error information to clients, but
it would be useful for administrators to know the cause of any errors.

Since we don't actually need any additional context here, we can remove
it. Since that allows us to avoid calling `context()` with the
`WriteError` context selector, we can then safely rename `WriteError` to
`Write`.

Make this specifically about errors writing instead of a generic I/O
error.

Name the variant `WriteError` instead of `Write` because Snafu will
generate context selector structs with these names and we already have a
`Write` identifier imported.

If we get errors building the request or Conduit errors, respond with a
500 error. Otherwise, it's a write error, and we should do nothing
(ideally log the error), because this means the client closed the
connection or there are bigger problems.