The arm selecting the Prisma adapter.
options.prismaClient is required by the union rather than optional on a
nested bag, so a registration that forgets it is a compile error instead of
a connect() throw — the same guarantee the 'custom' arm gives adapter.
readonly
type: "prisma"
Selects the Prisma arm.
readonly
options: PrismaAdapterOptions
Prisma adapter configuration; prismaClient is required.