在GoLang中构造空数组的最佳实践？

I'm wondering about best practices when initializing empty arrays.

i.e. Is there any difference here between arr1, arr2, and arr3?

myArr1 := []int{}
myArr2 := make([]int,0)
var myArr3 []int

[]int

/tldr

1. Is there any difference between the 3 ways to make an empty array?
2. What is the default capacity of an array when unspecified?
3. What is the performance cost of using arrays with unspecified capacity?