refactor the error handling and optimize the heap allocation

cmd/slicewriter/dummy_test.go

@@ -0,0 +1,40 @@
+package slicewriter
+
+import (
+	"sync"
+	"testing"
+)
+
+func TestDummy(t *testing.T) {
+	var (
+		p    sync.Pool
+		a, b []byte
+	)
+
+	p = sync.Pool{
+		New: func() any {
+			return make([]byte, 4096)
+		},
+	}
+
+	a = p.Get().([]byte)
+	t.Logf("retrieve a from pool: len %d, cap %d", len(a), cap(a))
+
+	b = p.Get().([]byte)
+	t.Logf("retrieve b from pool: len %d, cap %d", len(b), cap(b))
+
+	a = a[:1024]
+	b = b[:1024]
+	t.Logf("resize a : len %d, cap %d", len(a), cap(a))
+	t.Logf("resize b : len %d, cap %d", len(b), cap(b))
+
+	p.Put(a[:cap(a)])
+	p.Put(b)
+
+	t.Log("after putting back")
+	a = p.Get().([]byte)
+	t.Logf("retrieve a from pool: len %d, cap %d", len(a), cap(a))
+
+	b = p.Get().([]byte)
+	t.Logf("retrieve b from pool: len %d, cap %d", len(b), cap(b))
+}