support useLocalSessionState config, default is true

src/main/java/com/alibaba/druid/pool/DruidPooledConnection.java

@@ -830,6 +830,13 @@ public class DruidPooledConnection extends PoolableWrapper implements javax.sql.
     @Override
     public void setReadOnly(boolean readOnly) throws SQLException {
         checkState();
+        
+        boolean useLocalSessionState = holder.getDataSource().isUseLocalSessionState();
+        if (useLocalSessionState) {
+            if (readOnly == holder.isUnderlyingReadOnly()) {
+                return;
+            }
+        }
 
         conn.setReadOnly(readOnly);
         holder.setUnderlyingReadOnly(readOnly);
@@ -859,6 +866,13 @@ public class DruidPooledConnection extends PoolableWrapper implements javax.sql.
     @Override
     public void setTransactionIsolation(int level) throws SQLException {
         checkState();
+        
+        boolean useLocalSessionState = holder.getDataSource().isUseLocalSessionState();
+        if (useLocalSessionState) {
+            if (level == holder.getUnderlyingTransactionIsolation()) {
+                return;
+            }
+        }
 
         conn.setTransactionIsolation(level);
         holder.setUnderlyingTransactionIsolation(level);
@@ -902,6 +916,13 @@ public class DruidPooledConnection extends PoolableWrapper implements javax.sql.
     @Override
     public void setHoldability(int holdability) throws SQLException {
         checkState();
+        
+        boolean useLocalSessionState = holder.getDataSource().isUseLocalSessionState();
+        if (useLocalSessionState) {
+            if (holdability == holder.getUnderlyingHoldability()) {
+                return;
+            }
+        }
 
         conn.setHoldability(holdability);
         holder.setUnderlyingHoldability(holdability);