curl --request POST \
  --url https://studio.edgeimpulse.com/v1/api/{projectId}/split-preview \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "trainingSplitRatio": 123,
  "testingSplitRatio": 123,
  "validationSplitRatio": 123,
  "excludeDisabledSamples": false,
  "stratifyBy": {
    "label": true,
    "metadataKeys": [
      "<string>"
    ]
  },
  "keepTogetherMetadataKeys": [
    "<string>"
  ]
}
'

{
  "success": true,
  "data": {
    "assignmentPreview": {
      "title": "<string>",
      "keyLabel": "<string>",
      "rows": [
        {
          "stratValue": "<string>",
          "sampleCount": 123,
          "percentWithinGroup": 123,
          "totalLengthMs": 123,
          "percentWithinGroupDuration": 123
        }
      ],
      "summary": "<string>"
    },
    "balancePreviews": [
      {
        "title": "<string>",
        "keyLabel": "<string>",
        "rows": [
          {
            "stratValue": "<string>",
            "sampleCount": 123,
            "percentWithinGroup": 123,
            "totalLengthMs": 123,
            "percentWithinGroupDuration": 123
          }
        ],
        "summary": "<string>"
      }
    ]
  },
  "error": "<string>"
}