@Override
 public void setCPU(float cpu) {
   maybeInitBuilder();
   builder.setCpu(cpu);
 }
 @Override
 public void setPhysicalMemory(int pmem) {
   maybeInitBuilder();
   builder.setPmem(pmem);
 }
 @Override
 public void setVirtualMemory(int vmem) {
   maybeInitBuilder();
   builder.setVmem(vmem);
 }
 public ResourceUtilizationProto getProto() {
   proto = viaProto ? proto : builder.build();
   viaProto = true;
   return proto;
 }