multipart.Writer.CreateFormFile should accept content type as a parameter

[gopherbot]

by t.manki:

Hi,

Thanks for adding a multipart writer.  When a file is added to the form, content type of
the file is now hard-coded as octet stream (see
http://goneat.org/src/pkg/mime/multipart/writer.go#L97).  It's crucial that callers have
control over the content type.  Without setting the correct content type, Flickr API
rejects the content, for example.

Thanks.

Kannan

[rsc]

Comment 1:

Owner changed to @bradfitz.

Status changed to Accepted.

[bradfitz]

Comment 2:

You can just use Writer.CreatePart.
The others ones are just for convenience.  If they're not convenient, don't use them.
*shrug*

Labels changed: added priority-low, removed priority-medium.

[rsc]

Comment 3:

Status changed to WorkingAsIntended.