fix code

hutool-core/pom.xml

@@ -9,7 +9,7 @@
 	<parent>
 		<groupId>cn.hutool</groupId>
 		<artifactId>hutool-parent</artifactId>
-		<version>6.0.0.M1</version>
+		<version>6.0.0.M2</version>
 	</parent>
 
 	<artifactId>hutool-core</artifactId>

hutool-core/src/main/java/cn/hutool/core/io/stream/SyncInputStream.java

@@ -48,15 +48,15 @@ public class SyncInputStream extends FilterInputStream {
 
 	/**
 	 * 同步数据到内存
+	 * @return this
 	 */
-	public void sync() {
-		if (false == asyncFlag) {
-			// 已经是同步模式
-			return;
+	public SyncInputStream sync() {
+		if (asyncFlag) {
+			this.in = new ByteArrayInputStream(readBytes());
+			this.asyncFlag = false;
 		}
 
-		this.in = new ByteArrayInputStream(readBytes());
-		this.asyncFlag = false;
+		return this;
 	}
 
 	/**