docs: protected byte[] generateMultipartBoundary() {
  		byte[] boundary = new byte[rnd.nextInt(11) + 30];
  		for (int i = 0; i < boundary.length; i++) {
  			boundary[i] = BOUNDARY_CHARS[rnd.nextInt(BOUNDARY_CHARS.length)];
  		}
  		return boundary;
  	}