public void addHeader(String name,String value){
  if (customHeaders == null) {
    customHeaders=new HashMap<>(2);
  }
  List<String> header=customHeaders.get(name);
  if (header == null) {
    header=new ArrayList<>();
    customHeaders.put(name,header);
  }
  header.add(value);
}

public void addHeader ( String name , String value ) { if ( customHeaders == null ) { customHeaders = new HashMap < > ( 2 ) ; } List < String > header = customHeaders . get ( name ) ; if ( header == null ) { header = new ArrayList < > ( ) ; customHeaders . put ( name , header ) ; } header . add ( value ) ; }
add a custom header .
