Fix the zlibWriterPools doesn't work leads to high memory usage (#645)

Co-authored-by: dengzhiwen1 <dengzhiwen1@xiaomi.com>
diff --git a/internal/utils/compression.go b/internal/utils/compression.go
index 4ad2ced..379cdf2 100644
--- a/internal/utils/compression.go
+++ b/internal/utils/compression.go
@@ -53,7 +53,7 @@
 
 	buf := bufPool.Get().(*bytes.Buffer)
 	defer bufPool.Put(buf)
-	writerPool := zlibWriterPools[compressLevel-1]
+	writerPool := &zlibWriterPools[compressLevel-1]
 	writer := writerPool.Get().(*zlib.Writer)
 	defer writerPool.Put(writer)
 	buf.Reset()