Cannot set multipart mime-type to a value with semi-colons in it

[jagregory]

Calling multiPart with a mime-type that has a parameter, which is a valid mime-type, results in an error:

.multiPart("file", "{}", "application/vnd.test;version=1")

Error:

MIME type may not contain reserved characters
	at org.apache.http.util.Args.check(Args.java:36)
	at org.apache.http.entity.ContentType.create(ContentType.java:229)
	at org.apache.http.entity.mime.content.StringBody.<init>(StringBody.java:113)

The org.apache.http.entity.ContentType.create function does not permit values with parameters, you need to use the ContentType.parse function instead, but there's no way (that I can see) in rest-assured to pass your own ContentType instance, only strings.