docs: public void setContentDispositionFormData(String name, String filename) {
  		Assert.notNull(name, "'name' must not be null");
  		StringBuilder builder = new StringBuilder("form-data; name=\"");
  		builder.append(name).append('\"');
  		if (filename != null) {
  			builder.append("; filename=\"");
  			builder.append(filename).append('\"');
  		}
  		set(CONTENT_DISPOSITION, builder.toString());
  	}