Github user roshannaik commented on a diff in the pull request:
https://github.com/apache/storm/pull/2502#discussion_r168033940
--- Diff:
storm-client/src/jvm/org/apache/storm/executor/spout/SpoutOutputCollectorImpl.java
---
@@ -22,19 +22,23 @@
import org.apache.storm.executor.TupleInfo;
import org.apache.storm.spout.ISpout;
import org.apache.storm.spout.ISpoutOutputCollector;
+import org.apache.storm.tuple.AddressedTuple;
import org.apache.storm.tuple.MessageId;
import org.apache.storm.tuple.TupleImpl;
import org.apache.storm.tuple.Values;
-import org.apache.storm.utils.Utils;
import org.apache.storm.utils.MutableLong;
import org.apache.storm.utils.RotatingMap;
+import org.apache.storm.utils.Utils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
+// Methods are not thread safe. Each thread expected to have a separate
instance, or else synchronize externally
--- End diff --
To nail down and document the concurrent emits semantics I had opened
[STORM-2945](https://issues.apache.org/jira/browse/STORM-2945)
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