Feat[pool]: add NewSizedBufferFactory

pool/bytes.go

@@ -18,6 +18,14 @@ func NewBufferFactory() BufferFactory {
 	}
 }
 
+func NewSizedBufferFactory(size int) BufferFactory {
+	return BufferFactory{
+		pool: &sync.Pool{
+			New: func() any { return bytes.NewBuffer(make([]byte, size)) },
+		},
+	}
+}
+
 func (cf BufferFactory) Put(buf *Buffer) error {
 	var err = ErrBufferReturned
 	buf.o.Do(func() {

pool/bytes_test.go

@@ -496,4 +496,13 @@ func TestBufferFactory(t *testing.T) {
 			t.Fatalf("The slice is not nil")
 		}
 	})
+	t.Run("NewSizedBufferFactory", func(t *testing.T) {
+		t.Parallel()
+		sized := NewSizedBufferFactory(4)
+		buf := sized.Get()
+		defer sized.MustPut(buf)
+		if buf.Cap() != 4 {
+			t.Errorf("Expected sized buffer from fresh factory to be cap == 4, got: %d", buf.Cap())
+		}
+	})
 }