NewMessageEnvelope creates a new MessageEnvelope for the specified payload with attributes from the specified context.

NewMessageEnvelopeForRequest creates a new MessageEnvelope for sending request to EdgeX via internal MessageBus to target Device Service.

NewMessageEnvelopeForResponse creates a new MessageEnvelope for sending response from Device Service back to Core Command.

NewMessageEnvelopeFromJSON creates a new MessageEnvelope by decoding the message payload received from external MQTT in order to send request via internal MessageBus.

NewMessageEnvelopeWithError creates a new MessageEnvelope with ErrorCode set to 1 indicating there's error and the payload contains message string about the error.

HostInfo is the URL information of the host as the following scheme: <Protocol>://<Host>:<Port>.

MessageBusConfig defines the messaging information need to connect to the message bus in a publish-subscribe pattern.

MessageEnvelope is the data structure for messages.

TopicChannel is the data structure for subscriber.