code: public byte[] encode(T t) {
          if (t == null) {
              if (!nullable) {
                  throw new InvalidArgument("cannot encode a null type");
              }
              return getNullValue();
          }
          return encodeType(t);
      }
docs: Encodes the column's type.
  
  @param t {@code <T>}
  @return {@code byte[]}