public byte[] execProcedureWithRet(String signature, String instance,
Map<String, String> props) throws IOException {
ProcedureDescription.Builder builder = ProcedureDescription.newBuilder();
builder.setSignature(signature).setInstance(instance);
for (Entry<String, String> entry : props.entrySet()) {
NameStringPair pair = NameStringPair.newBuilder().setName(entry.getKey())
.setValue(entry.getValue()).build();
builder.addConfiguration(pair);
}
final ExecProcedureRequest request = ExecProcedureRequest.newBuilder()