Add correlation_id to TransactionCreateRequest and TransactionHeader

Callers can set correlation_id when creating transactions to link
related transactions together (e.g. all transactions in a workflow).
The field propagates through the PRIME pipeline and child transactions.

models/models.go

@@ -5,10 +5,11 @@ const (
 )
 
 type TransactionCreateRequest struct {
-	Version string `json:"version,omitempty"`
-	TxnType string `json:"txn_type"`
-	Payload string `json:"payload"`
-	Tag     string `json:"tag,omitempty"`
+	Version       string `json:"version,omitempty"`
+	TxnType       string `json:"txn_type"`
+	Payload       string `json:"payload"`
+	Tag           string `json:"tag,omitempty"`
+	CorrelationId string `json:"correlation_id,omitempty"`
 }
 
 type TransactionCreateResponse struct {
@@ -35,13 +36,14 @@ type Transaction struct {
 }
 
 type TransactionHeader struct {
-	Tag       string `json:"tag"`
-	DcId      string `json:"dc_id"`
-	TxnId     string `json:"txn_id"`
-	Invoker   string `json:"invoker"`
-	BlockId   string `json:"block_id"`
-	TxnType   string `json:"txn_type"`
-	Timestamp string `json:"timestamp"`
+	Tag           string `json:"tag"`
+	DcId          string `json:"dc_id"`
+	TxnId         string `json:"txn_id"`
+	Invoker       string `json:"invoker"`
+	BlockId       string `json:"block_id"`
+	TxnType       string `json:"txn_type"`
+	Timestamp     string `json:"timestamp"`
+	CorrelationId string `json:"correlation_id,omitempty"`
 }
 
 type TransactionProof struct {