- metadata<const T, const S, const M>(val, metadata): CompiledSchema<T, {
[K in keyof (S & Record<"metadata", M>)]: (S & Record<"metadata", M>)[K]
}> Returns CompiledSchema<T, {
[K in keyof (S & Record<"metadata", M>)]: (S & Record<"metadata", M>)[K]
}>
add metadata to a schema