Optional ReadonlyaskPuts the reply question to the user; see MessagingRegistryOptions.askReply.
Optional ReadonlybackendsBackend constructors; a provider without one stays unavailable.
Optional ReadonlysignerThe active account's signer, read on every availability check. When given,
private, ratchet and group are available only while it has nip44 and
legacy only while it has nip04, whichever backend is supplied for them.
Readonlystorage
Options for createDefaultMessaging.