otherwise it rejects the message with a 550 error.  Also, the LMTP server
   adds the `X-Message-ID-Hash` header automatically.  The `inject` cli
   command will also add the `X-Message-ID-Hash` header, but it will craft a
   `Message-ID` header first if one is missing from the injected text.  Also,
   `inject` will always set the correct value for the `original_size`
   attribute on the message object, instead of trusting a possibly incorrect
   value if it's already set.  The individual `IArchiver` implementations no
   longer set the `X-Message-ID-Hash` header.