Function set 

pub fn set(
    bucket: &Bucket,
    key: &str,
    outgoing_value: &OutgoingValue,
) -> Result<(), Error>

Set the value associated with the key in the bucket. If the key already exists in the bucket, it overwrites the value.

If the key does not exist in the bucket, it creates a new key-value pair.

If any other error occurs, it returns an Err(error).