Creating Custom Message Header Fields
To create a custom message header field, you can create a map with custom user properties fields. The user properties are carried in the message separate from the payload.
To create custom message header fields, first create an SDT map with custom user properties fields, then pass it to the setUserPropertyMap function when you use the Solace JavaScript API API.
To create a user properties map, call solace.Message.setUserPropertyMap(...) and pass in an existing SDT.