SubscriptionError type
Errors found while setting up subscriptions, separated out by reason:
- 
internal: An opaque internal error
- 
unknownSubscriber: The media node requesting the subscription does not exist
- 
multipleStreams: Multiple stream keys found for the context type
- 
sourceSubscriptionError: Per-source errors
Signature:
export type SubscriptionError = {
    info: string;
    reason: "internal";
} | {
    mediaNodeId: MediaNodeId;
    reason: "unknownSubscriber";
} | {
    contextType: ContextType;
    streamKeys: StreamKey[];
    reason: "multipleStreams";
} | {
    sourceErrors: SourceSubscriptionError[];
    reason: "sourceSubscriptionError";
};References: MediaNodeId, ContextType, StreamKey, SourceSubscriptionError