Function prepare_custom_data_batch 

pub fn prepare_custom_data_batch(
    data: Vec<CustomData>,
) -> Result<(RecordBatch, String, Option<String>, UnixNanos, UnixNanos)>

Prepares a batch of custom data for writing: encodes to Arrow, augments with data_type column, and returns type identity and timestamp range so the catalog can build path and perform I/O.

Errors

Returns an error if encoding or augmentation fails, or if the type is not registered.