apply
inline fun apply(describe: String, exists: () -> Boolean = { false }, create: () -> Unit, validate: () -> Unit)
Makes sure of the structure describe names as this mode says, with the backend's native checks: under AUTO creates it unless exists says it is there, and validates it when it is; under VALIDATE refuses it, naming it, when it does not exist, and validates it when it does; under NONE does nothing. A backend whose create is idempotent and checks what it finds leaves exists out: it then always creates.