Function write 

pub fn write(
    store: &Path,
    ids: &[&str],
    kind: &str,
    note: Option<&str>,
    by: &str,
    now: i64,
    version: &dyn Fn(&str) -> Option<u32>,
) -> Result<Vec<Record>>

Appends one record per id (in order, each once) to the store’s log, each line in one write (learn.rs append_line). version gives a lesson’s current version for an absorb (None: not in the store yet); a release carries neither note nor version. Returns the records written.

Errors

When a line cannot be appended; the records before it are written.