A context with no client channel: notifications are dropped and
server->client requests are rejected. Used by transports that do not (yet)
support streaming, and as the default when none is supplied.
The exception thrown by the server->client primitives when this context
has no channel. Overridable so a context can give a transport-specific
message while inheriting the three throwing primitives.
A context with no client channel: notifications are dropped and server->client requests are rejected. Used by transports that do not (yet) support streaming, and as the default when none is supplied.