Capabilities the supported featureset of the data exchange interface implemented by the plugin, with the specified config.

Callbacks is the interface provided to the data exchange plugin, to allow it to pass events back to firefly.

Plugin is the interface implemented by each data exchange plugin Data exchange plugins are responsible for qualities of service for: - Storage of large data payloads - Security of transfer of data between participants (transport and payload authorization & encryption) - Reliability of transfer of data between participants (many transports can be supported - HTTPs/AMQP/MQTT etc.) Each plugin must handle network addressing, as well as transfer of messages and BLOBs.