code: function (value, offset) {
                  if (undefined === offset) {
                      offset = this.offset;
                  }
                  this.writeInt32(Math.round(value * 65536), offset);
  
                  return this;
              }
docs: 写入fixed类型
  
  @param {number} value 写入值
  @param {number=} offset 偏移
  @return {number} float