The first thing someone will ask when someone sees this method is
"Why doesn't `send` just accept `Attachment`?". This question is fair
but it has an issue: exception propagation becomes confusing.
When we save a file and write it to memory an HTTP request is sent
similar to other API calls. Like all HTTP requests, these can fail.
Since these requests denote failure using HTTPException, if it were to
originate within `send` then it becomes confusing to know whether the
attachment saving itself failed or whether the sending failed.
For that reason, and to keep in-line with only 1 type of HTTP call per
method, it doesn't make sense for `send` to support `Attachment`.
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