How to use res.send([buffer]) without a content-type?

[jeroen]

I refactored my app to use in memory buffers instead of files. However an undesired side effect is that for all responses where we do res.send(buf) without setting an explicit res.type() express now defaults to:

Content-Type: application/octet-stream

I do not want this. Is there a workaround to use res.send(buffer) without setting any content-type automatically?

I know I can explicitly override it with res.type("bla/bla") but for many resources there is not a known type. In these cases I want to set no content-type response header.

I am using express 5.0.1.