Function cast_to_run_end_encoded 

pub(crate) fn cast_to_run_end_encoded<K: RunEndIndexType>(
    array: &ArrayRef,
    value_type: &DataType,
    cast_options: &CastOptions<'_>,
) -> Result<ArrayRef, ArrowError>

Attempts to encode an array into a RunArray with index type K and value type value_type