Summation of rows of array without allocation

Suppose we have an array x with m rows and n columns and a vector s with m elements. I would like to sum the elements of each row of array x and save these results in vector s.

This can be easily implemented in Julia using v = sum(x, dims = 2). However, this procedure allocates extra memory for the operation. Is it any way to do this operation without extra allocation (and not using cycles)? I was trying function sum!, but it does not accept keyword argument dims.

I found the solution: sum!(v, x)