PURE invariant: an Outbound bridge must have somewhere to go — an Address (join URL / phone
number) or an ExternalConnectionID (an already-established connection to attach to). Returns
the error, or null when valid (Inbound bridges are exempt — the endpoint comes to the agent).
PURE invariant: an
Outboundbridge must have somewhere to go — anAddress(join URL / phone number) or anExternalConnectionID(an already-established connection to attach to). Returns the error, ornullwhen valid (Inbound bridges are exempt — the endpoint comes to the agent).