code: public void addParam(String name, InputStream stream, String contentType, String filename) {
  		if (this.method != HttpMethod.POST)
  			throw new IllegalStateException("May only add binary attachment to POST, not to " + this.method);
  		
  		this.params.put(name, new BinaryAttachment(stream, contentType, filename));
  		this.hasBinaryAttachments = true;
  	}
docs: Adds a binary attachment. Request method must be POST; causes the type to be multipart/form-data