code: public UnsignedIntegerTag setValue(long value) {
          this.value = value;
          byte length = 1;
          long v = (value + 1) >> BIT_IN_BYTE;
          while (v > 0) {
              length++;
              v = v >> BIT_IN_BYTE;
          }
          size = VINT.fromValue(length);
          return this;
      }
docs: setter for value, updates the size of this tag
  
  @param value
  - value to be set
  @return - this for chaining