DecodeIDMessage decode a json object of the form `{"id": id}` where the id must be uint.

EncodeIDMessage encode the id into a json object of the form `{"id": id}`.

EncodeStringIDMessage encode the id into a json object of the form `{"id": id}`.

NewClient creates a new Client initialized with the given AMQP URI and durable Topic Exchange name.

Client provides a simple interface for connecting to RabbitMQ, declaring a channel, and declaring a durable Topic Exchange, which is used by various pub/sub operations all along the program.