Major Description
Axiom currently uses JavaMail to produce MIME messages. Since JavaMail expects the content of a part to be provided as a DataHandler object, this means that the root part (i.e. the SOAP message) cannot be streamed and must be buffered in memory, generating unnecessary overhead. Axiom 1.2.9 introduced a new API called MultipartWriter with a contract that allows streaming. Since the default implementation currently uses JavaMail, that option is not used.
The task is to write an alternative implementation of MultipartWriter that avoids buffering the root part and that is optimized for XOP and SwA (where e.g. it is not necessary to take into account stuff like 7bit encoding). Maybe it is possible to use an existing library (mime4j?) for this.