Unix time — c.Time64()

8-byte unsigned seconds since epoch, exposed as Date in TypeScript (bigint on the wire as u64):

@c.struct()
class Event {
  @c.field(c.Time64())
  when!: Date;
}

C equivalent:

typedef struct {
    uint64_t when; /* seconds since 1970-01-01 UTC */
} Event;

Use the same endianness as the surrounding struct ("little" / "big" in c.read / c.write).