panic: runtime error: index out of range [3] with length 3

goroutine 1 [running]:
main.processItems({0xc000018180, 0x3, 0x3})
	/home/user/project/main.go:15 +0x9e
main.main()
	/home/user/project/main.go:23 +0x68
exit status 2
