* @return A Map of key/value configurations we got from the Master else
* null if we failed to register.
* @throws IOException
*/
private RegionServerStartupResponse reportForDuty() throws IOException {
RegionServerStartupResponse result = null;
Pair<ServerName, RegionServerStatusService.BlockingInterface> p =
createRegionServerStatusStub();
this.rssStub = p.getSecond();
ServerName masterServerName = p.getFirst();
if (masterServerName == null) return result;