Cache split.splitId() result in a local variable to avoid calling the method twice per iteration:

  - Clarity: Makes it explicit that both usages refer to the same value, improving readability.
  - Consistency: Eliminates any theoretical risk if splitId() were ever changed to a non-pure method in the future.
  - Minor efficiency: Avoids a redundant method dispatch on every iteration of the loop.

Author: ThorneANN

flink-cdc-connect/flink-cdc-source-connectors/flink-connector-mysql-cdc/src/main/java/org/apache/flink/cdc/connectors/mysql/source/assigners/MySqlSnapshotSplitAssigner.java

@@ -390,11 +390,12 @@ public List<FinishedSnapshotSplitInfo> getFinishedSplitInfos() {
                 new ArrayList<>(assignedSplits.values());
         List<FinishedSnapshotSplitInfo> finishedSnapshotSplitInfos = new ArrayList<>();
         for (MySqlSchemalessSnapshotSplit split : assignedSnapshotSplit) {
-            BinlogOffset binlogOffset = splitFinishedOffsets.get(split.splitId());
+            String splitId = split.splitId();
+            BinlogOffset binlogOffset = splitFinishedOffsets.get(splitId);
             finishedSnapshotSplitInfos.add(
                     new FinishedSnapshotSplitInfo(
                             split.getTableId(),
-                            split.splitId(),
+                            splitId,
                             split.getSplitStart(),
                             split.getSplitEnd(),
                             binlogOffset));