cq5 - How to invoke a workflow providing data/arguments using Java API -

i've followed https://helpx.adobe.com/experience-manager/using/invoking-experience-manager-workflows-using.html , can invoke workflow using java api. i'm trying tweak example can start workflow metadatamap containing key value pairs steps work with. log message prints key , value sets. steps in workflow not have data. how pass metadatamap workflow when starting java api?

@override public string startworkflow(string workflowname, string workflowcontent, metadatamap metamap) {      try     {         //invoke adaptto method create session          resourceresolver resourceresolver = writeservice.getresolver();         session = resourceresolver.adaptto(session.class);          //create workflow session          workflowsession wfsession = workflowservice.getworkflowsession(session);          // workflow model         workflowmodel wfmodel = wfsession.getmodel(workflowname);             // workflow data         // first param in newworkflowdata method payloadtype.           // fancy name let know type of workflow working with.         workflowdata wfdata = wfsession.newworkflowdata("jcr_path", workflowcontent);         metadatamap mdp = wfdata.getmetadatamap();         for(entry<string, object> entry: metamap.entryset()){             log.info("wf args entry="+ entry.getkey()+" "+entry.getvalue());             mdp.put(entry.getkey(), entry.getvalue());         }         // run workflow.          wfsession.startworkflow(wfmodel, wfdata, mdp);          return workflowname +" has been invoked on content: "+workflowcontent ;      }     catch(exception e)     {         e.printstacktrace();     }      return null; } 

i believe trying data parameter of execute method - metadatamap, instead, workitem object, workitem.getworkflowdata().getmetadatamap().