add additional metadata to message, closes #194

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

subscriber.go

@@ -271,7 +271,11 @@ func (pc *consumer) consume() {
 				for _, hdr := range record.Headers {
 					pm.hdr.Set(hdr.Key, string(hdr.Value))
 				}
-
+				pm.hdr.Set("Micro-Offset", strconv.FormatInt(record.Offset, 10))
+				pm.hdr.Set("Micro-Partition", strconv.FormatInt(int64(record.Partition), 10))
+				pm.hdr.Set("Micro-Topic", record.Topic)
+				pm.hdr.Set("Micro-Key", string(record.Key))
+				pm.hdr.Set("Micro-Timestamp", strconv.FormatInt(record.Timestamp.Unix(), 10))
 				switch h := pc.handler.(type) {
 				case func(broker.Message) error:
 					err = h(pm)