[MINOR] refactor: Check debug enabled (apache#1793)

### What changes were proposed in this pull request?

Address apache#1789 (comment)

### Why are the changes needed?

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

minor fix

client-spark/common/src/main/java/org/apache/spark/shuffle/writer/BufferManagerOptions.java

@@ -64,10 +64,13 @@ public BufferManagerOptions(SparkConf sparkConf) {
             RssSparkConfig.RSS_WRITER_PRE_ALLOCATED_BUFFER_SIZE.defaultValue().get());
     requireMemoryInterval = sparkConf.get(RssSparkConfig.RSS_WRITER_REQUIRE_MEMORY_INTERVAL);
     requireMemoryRetryMax = sparkConf.get(RssSparkConfig.RSS_WRITER_REQUIRE_MEMORY_RETRY_MAX);
-    LOG.debug(RssSparkConfig.RSS_WRITER_BUFFER_SIZE.key() + "=" + bufferSize);
-    LOG.debug(RssSparkConfig.RSS_WRITER_BUFFER_SPILL_SIZE.key() + "=" + bufferSpillThreshold);
-    LOG.debug(
-        RssSparkConfig.RSS_WRITER_PRE_ALLOCATED_BUFFER_SIZE.key() + "=" + preAllocatedBufferSize);
+    if (LOG.isDebugEnabled()) {
+      LOG.debug(
+          "New buffer manager options, bufferSize: {}, bufferSpillThreshold: {}, preAllocatedBufferSize: {}",
+          bufferSize,
+          bufferSpillThreshold,
+          preAllocatedBufferSize);
+    }
     checkBufferSize();
   }