Function write_private_tree 

pub fn write_private_tree(
    context: &GitContext,
    cwd: &Path,
    commit_index: &Path,
    object_directory: &Path,
) -> Result<String, GitFailure>

What: Writes the intended tree from the private index into the shadow object store. Why: The tree is the exact content the commit will carry.

In TS you’d write (pseudocode):

await writePrivateTree({ workspace, gitPath, cwd });