Function create 

pub fn create(
    root: &Path,
    container: &Path,
    content_name: &str,
) -> Result<Session>

Start a session under root, creating the tree if it is not there.

The container path is resolved before it is written down, so a container reached through a symbolic link records the file rather than the link, and so that what recovery reads later is a path and not a relative fragment interpreted against whatever directory a later process happens to be in.

Errors

Where the container cannot be resolved, or the tree cannot be created.