png encoder pool 추가

image/png_encoder_buf_pool.go

@@ -0,0 +1,22 @@
+package util
+
+import (
+	"sync"
+	"image/png"
+)
+
+type PNGEncoderBufPool struct {
+	pool sync.Pool
+}
+
+func (p *PNGEncoderBufPool) Get() *png.EncoderBuffer {
+	v := p.pool.Get()
+	if v == nil {
+		return &png.EncoderBuffer{}
+	}
+	return v.(*png.EncoderBuffer)
+
+}
+func (p *PNGEncoderBufPool) Put(buf *png.EncoderBuffer) {
+	p.pool.Put(buf)
+}