Event being reacted to
OptionalgetEventRelayHint: (eventId: string) => Promise<string | undefined>Optional function to get relay hint for event ID
OptionalgetPubkeyRelayHint: (pubkey: string) => Promise<string | undefined>Optional function to get relay hint for pubkey
Includes NIP-25 "e", "p", "k", and "a" tags for a reaction event to point to a parent event