Clear identification of test markers in testcase call messages

[lambiase]

When running this test with pytest-fluent:

import pytest


@pytest.mark.simple
def test_simple():
    """
    Simple test always passing
    """
    assert True

I would like to be able to identify that simple was used as a marker for test_simple.

pytest-fluent sends a testcase call message containing a markers section.
However, it contains a mix of Python modules, actual markers, test methods in a
dictionary whose values are always 1:

    {
        "testId": "895ef55e-bad3-4a0d-b2f5-a55ce93d239c",
        "sessionId": "ca6c7a99-df62-432d-a187-3ec774adef75",
        "when": "call",
        "stage": "testcase",
        "markers": {
            "pytest-fluent": 1,
            "manual_tests/__init__.py": 1,
            "test_simple.py": 1,
            "pytestmark": 1,
            "simple": 1,
            "test_simple": 1
        },
        "duration": 0.0002015329991991166,
        "outcome": "passed",
        "name": "manual_tests/test_simple.py::test_simple"
    }

I think at the moment markers contains everything that could be matched against when using the pytest keyword parameter (-k) - it probably has this pseudo-dictionary structure for fast read/write operations.
It would probably make sense to have under markers the actual pytest markers (in the example above simple) and remove all the rest. Alternatively, if we believe that the contained information is useful, I would propose to change its structure to a list, and call the property keywords.