parallel: remove mutex from Map and Times

The slice is pre-allocated, a mutex is not needed.

parallel/slice.go

@@ -7,7 +7,6 @@ import "sync"
 func Map[T any, R any](collection []T, iteratee func(T, int) R) []R {
 	result := make([]R, len(collection))
 
-	var mu sync.Mutex
 	var wg sync.WaitGroup
 	wg.Add(len(collection))
 
@@ -15,9 +14,7 @@ func Map[T any, R any](collection []T, iteratee func(T, int) R) []R {
 		go func(_item T, _i int) {
 			res := iteratee(_item, _i)
 
-			mu.Lock()
 			result[_i] = res
-			mu.Unlock()
 
 			wg.Done()
 		}(item, i)
@@ -50,7 +47,6 @@ func ForEach[T any](collection []T, iteratee func(T, int)) {
 func Times[T any](count int, iteratee func(int) T) []T {
 	result := make([]T, count)
 
-	var mu sync.Mutex
 	var wg sync.WaitGroup
 	wg.Add(count)
 
@@ -58,9 +54,7 @@ func Times[T any](count int, iteratee func(int) T) []T {
 		go func(_i int) {
 			item := iteratee(_i)
 
-			mu.Lock()
 			result[_i] = item
-			mu.Unlock()
 
 			wg.Done()
 		}(i)