perf：升级Ip2Region

springboot-util/src/main/java/com/tiesheng/util/ip2region/Header.java

@@ -0,0 +1,34 @@
+package com.tiesheng.util.ip2region;
+
+/**
+ * @author hao
+ */
+public class Header {
+    public final int version;
+    public final int indexPolicy;
+    public final int createdAt;
+    public final int startIndexPtr;
+    public final int endIndexPtr;
+    public final byte[] buffer;
+
+    public Header(byte[] buff) {
+        assert buff.length >= 16;
+        version = Searcher.getInt2(buff, 0);
+        indexPolicy = Searcher.getInt2(buff, 2);
+        createdAt = Searcher.getInt(buff, 4);
+        startIndexPtr = Searcher.getInt(buff, 8);
+        endIndexPtr = Searcher.getInt(buff, 12);
+        buffer = buff;
+    }
+
+    @Override
+    public String toString() {
+        return "{" +
+                "Version: " + version + ',' +
+                "IndexPolicy: " + indexPolicy + ',' +
+                "CreatedAt: " + createdAt + ',' +
+                "StartIndexPtr: " + startIndexPtr + ',' +
+                "EndIndexPtr: " + endIndexPtr +
+                '}';
+    }
+}