Write an answer in Golang

There is an array A made of N integers. Your task is to choose as many integers from A as possible so that, when they are put in ascending order, all of the differences between all pairs of consecutive integers are equal. For example, for A $=[4,3,5,1,4,4],$ you could choose $1,3,$ and $5($with differences equal to $2)$ or $4,4,$ and $4($with differences equal to $0).$ So$,$ answer in this case will be $3.$

What is the maximum number of integers that can be chosen? Write a function.

Example $1$ :

A $=[4,7,1,5,3],$ function should return $4.4$ integers $(7,1,5,3)$ when put in ascending order the difference between all consecutive integers is $2.$

Example $2$ :

A $=[12,12,12,15,10],$ function should return $3.$ It is optimal to chose all $3$ integers with value $12.$

Example $3$ :

A $=[18,26,18,24,24,20,22],$ function should return $5.5$ integers $(18,20,22,24,26)$ when put in ascending order the difference between all consecutive integers is $2.$ Notice that we cannot pick any other integers, even though they occur more than once.