public void writingRequestHeaders(){
  if (sentRequestMillis != -1) {
    throw new IllegalStateException();
  }
  sentRequestMillis=System.currentTimeMillis();
}

public void writingRequestHeaders ( ) { if ( sentRequestMillis != - 1 ) { throw new IllegalStateException ( ) ; } sentRequestMillis = System . currentTimeMillis ( ) ; }
called immediately before the transport transmits http request headers . this is used to observe the sent time should the request be cached .
