generate: change Record.TimestampDelta to a varlong
@@ -95,7 +95,7 @@ Record => not top level
Attributes: int8
// TimestampDelta is the millisecond delta of this record's timestamp
// from the record's RecordBatch's FirstTimestamp.
- TimestampDelta: varint
+ TimestampDelta: varlong
// OffsetDelta is the delta of this record's offset from the record's
// RecordBatch's FirstOffset.
//
