how to generate the position.bin

Hi, the position.bin consists of the position of node, but i see the ngraph.tobinary does not generate it. i want to exchange my own data to that format so i can use the ngraph.

Start by reading the ngraph.tobinary entry point and inspecting how position.bin is consumed by ngraph. Determine whether the needed outcome is documentation or a generation change, then document or support the path for converting user-provided node positions into the expected format.

Written by the indexing model from the issue text.