feat(BRIDGE-122): changed type; will rebase this commit

observability_types.go

@@ -1,14 +1,12 @@
 package proton
 
-import "time"
-
 type ObservabilityBatch struct {
 	Metrics []ObservabilityMetric `json:"Metrics"`
 }
 
 type ObservabilityMetric struct {
 	Name      string      `json:"Name"`
 	Version   int         `json:"Version"`
-	Timestamp time.Time   `json:"Timestamp"`
+	Timestamp int64       `json:"Timestamp"` // Unix timestamp
 	Data      interface{} `json:"Data"`
 }