Support for Server Sent Events content. It allows a server to stream
events to a client. Events are string (utf-8) encoded, and a proper
EventEncoder or EventDecoded must be available for your event payload type.
the event payload.
the event type (optional).
the event id (optional).
Decode the string event payload as a value of type A.
Encode the event payload as a string (utf-8).
Provides default EventDecoders.
Provides default EventEncoders.