code: function FixedType(schema, opts) {
    Type.call(this, schema, opts);
    if (schema.size !== (schema.size | 0) || schema.size < 1) {
      throw new Error(f('invalid %s size', this.branchName));
    }
    this.size = schema.size | 0;
    this._branchConstructor = this._createBranchConstructor();
    Object.freeze(this);
  }
docs: Avro fixed type. Represented simply as a `Buffer`.