Mechanism for Transmitter to pre-create stream asynchronously. #304
Description
two working partners might want to enable signal sharing for their mutual customers by default. Transmitting and Receiving party may have out-of-band trust establishment process that may be utilized to provision SSF stream.
E.g, say when a SCIM sync is created between an IDP and Service Provider -> an SSF event with session-related events might be pre-created by transmitting party.
Transmitter should be able to indicate to receiver that it has a pre-created stream for it to user and receiver should acknowledge and start receiving events right away.