const Int64:  brand(
  "Int64",
  BigInt,
  (value) =>
    globalThis.BigInt.asIntN(64, value) === value
      ? ok()
      : err<Int64Error>({ type: "Int64", value }),
  (error) =>
    The value ${safelyStringifyUnknownValue(error.value)} is not a valid signed 64-bit integer (Int64).,
) ;