package main

import (
    "fmt"
)

func main() {

    actions := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
    batchSize := 3
    batches := make([][]int, 0, (len(actions)+batchSize-1)/batchSize)

    for batchSize < len(actions) {
        actions, batches = actions[batchSize:], append(batches, actions[0:batchSize:batchSize])
    }
    batches = append(batches, actions)
    fmt.Println(batches)
}