Go的单向通道有什么意义？(What's the point of one

A read-only channel can be made read-only to whomever receives it, while the sender still has a two-way channel on which they can write. For example:

func F() <-chan int {
    // Create a regular, two-way channel.
    c := make(chan int)

    go func() {
        defer close(c)

        // Do stuff
        c <- 123
    }()

    // Returning it, implicitely converts it to read-only,
    // as per the function return value.
    return c
}

F()