Function try_collect_left 

pub(crate) fn try_collect_left(
    hash_join: &HashJoinExec,
    ignore_threshold: bool,
    threshold_byte_size: usize,
    threshold_num_rows: usize,
) -> Result<Option<Arc<dyn ExecutionPlan>>>

Tries to create a HashJoinExec in PartitionMode::CollectLeft when possible.

This function will first consider the given join type and check whether the CollectLeft mode is applicable. Otherwise, it will try to swap the join sides. When the ignore_threshold is false, this function will also check left and right sizes in bytes or rows.