Function run_batch 

pub fn run_batch(
    runtime: &Runtime,
    step: &Value,
    batch: &RecordBatch,
) -> Result<RecordBatch, String>

Run a wasm / container step on a batch: the batch is typed to the transform’s declared input signature (columns by name, cast safely — a value that does not fit lands null, a missing column is all null), run once, and the transform’s output batch returned as is.