diff --git a/internal/csync/doc.go b/internal/csync/doc.go
new file mode 100644
index 0000000000000000000000000000000000000000..b44fa2dac52172a8753e620e19f5c8d0a0481618
--- /dev/null
+++ b/internal/csync/doc.go
@@ -0,0 +1,3 @@
+// Package csync provides concurrent data structures for safe access in
+// multi-threaded environments.
+package csync
diff --git a/internal/csync/slices_test.go b/internal/csync/slices_test.go
index 414f6fe25047fa4bdbbaf205cde2c7568fcb4d28..8dafc1c1f4462dc45e2eb1fdeb71ffeacef260c1 100644
--- a/internal/csync/slices_test.go
+++ b/internal/csync/slices_test.go
@@ -260,22 +260,17 @@ func TestSlice(t *testing.T) {
 		var wg sync.WaitGroup
 
 		// Concurrent appends
-		for i := 0; i < numGoroutines; i++ {
-			wg.Add(1)
+		for i := range numGoroutines {
+			wg.Add(2)
 			go func(start int) {
 				defer wg.Done()
-				for j := 0; j < itemsPerGoroutine; j++ {
+				for j := range itemsPerGoroutine {
 					s.Append(start*itemsPerGoroutine + j)
 				}
 			}(i)
-		}
-
-		// Concurrent reads
-		for i := 0; i < numGoroutines; i++ {
-			wg.Add(1)
 			go func() {
 				defer wg.Done()
-				for j := 0; j < itemsPerGoroutine; j++ {
+				for range itemsPerGoroutine {
 					s.Len() // Just read the length
 				}
 			}()