Fix: Prepend simtime to ZMQ write() payload for consistency (Issue #244)

[GaneshPatil7517]

hey @pradeeban

Summary

Fixes #244 - ZMQ write() does not prepend simtime, breaking mixed ZMQ/file-based studies.

Problem

The write() function had inconsistent behavior between ZMQ and file-based paths:

• File path: Correctly prepends [simtime + delta] before writing
• ZMQ path: Sent raw val without simtime prefix

Since read() always expects inval[0] to be simtime, this caused:

• Data corruption in mixed topologies (ZMQ writer → file reader or vice versa)
• First data value incorrectly interpreted as simtime
• One fewer element returned than expected
• Silent wrong results

Solution

Modified the ZMQ write path to prepend simtime + delta to list payloads, matching file-based write behavior:

if isinstance(zmq_val, list):
    payload = [simtime + delta] + zmq_val
    zmq_p.send_json_with_retry(payload)
    simtime += delta
else:
    zmq_p.send_json_with_retry(zmq_val)

**Changes**
[concore.py](vscode-file://vscode-app/c:/Users/HP/AppData/Local/Programs/Microsoft%20VS%20Code/591199df40/resources/app/out/vs/code/electron-browser/workbench/workbench.html): Prepend simtime to ZMQ list payloads in [write()](vscode-file://vscode-app/c:/Users/HP/AppData/Local/Programs/Microsoft%20VS%20Code/591199df40/resources/app/out/vs/code/electron-browser/workbench/workbench.html)

[test_concore.py](vscode-file://vscode-app/c:/Users/HP/AppData/Local/Programs/Microsoft%20VS%20Code/591199df40/resources/app/out/vs/code/electron-browser/workbench/workbench.html): Updated test to expect simtime prefix

Testing
All 25 unit tests pass
Maintains backward compatibility for non-list ZMQ payloads
Preserves existing retry logic and error handling

[Copilot]

Pull request overview

Fixes inconsistency between file-based and ZMQ-based concore.write() by adding a simtime prefix to ZMQ list payloads, addressing Issue #244 where mixed ZMQ/file studies could misinterpret the first data element as simtime.

Changes:

• Prepend [simtime + delta] to ZMQ list payloads in concore.write() to match file write behavior.
• Update the ZMQ write unit test to expect the simtime-prefixed payload.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
concore.py	Adjusts ZMQ write() to prefix simtime for list payloads (aligning with file output format).
tests/test_concore.py	Updates test expectations to include simtime prefix in the ZMQ send payload.

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[pradeeban]

/gemini review