Iota

Go has a language feature, that when used with a type definition (and if you squint really hard), kinda looks like an enum (but it's not). It's called iota.

type sendingChannel int

const (
    Email sendingChannel = iota
    SMS
    Phone
)

The iota keyword is a special keyword in Go that creates a sequence of numbers. It starts at 0 and increments by 1 for each constant in the const block. So in the example above, Email is 0, SMS is 1, and Phone is 2.

Go developers sometimes use iota to create a sequence of constants to represent a set of related values, much like you would with an enum in other languages. But remember, it's not an enum. It's just a sequence of numbers.