@Test
 public void append() {
   rc.del(a("mykey"));
   eq(5, rc.append("mykey", "Hello"));
   eq(11, rc.append("mykey", " World"));
   eq("Hello World", rc.get("mykey"));
 }
 public Long append(byte[] key, byte[] value) {
   try {
     if (isPipelined()) {
       pipeline(pipeline.append(key, value));
       return null;
     }
     return client.append(key, value).data();
   } catch (Exception ex) {
     throw convertSrpAccessException(ex);
   }
 }