public MultipartEncoder(OutputStream out,String topBoundary){
  this.out=out;
  this.topBoundary=topBoundary;
  parts.add(topBoundary);
}

public MultipartEncoder ( OutputStream out , String topBoundary ) { this . out = out ; this . topBoundary = topBoundary ; parts . add ( topBoundary ) ; }
constructs a new multipart encoder with the given output stream and using the provided top - level boundary .
