sftp transfer status feedback?

[Patrick Higgins]

My project seems to be getting more and more difficult...my sftp-server
needs to be able to track successful uploads and downloads, and to
report these to a an external program when the client disconnects.

It looks like the sftp protocol is driven entirely by the client--it
makes requests and receives response codes and data. The server doesn't
seem to receive any feedback from the client about whether or not
something completed successfully. For instance, a client might request
an open followed by enough reads to get half of the file, and then
request a close. Without coding sophisticated (and mostly useless)
tracking, it would be difficult to know if the file was read in it's
entirety. Is my (limited) understanding more or less correct?

Is there a simple way to achieve this behavior? Is there a document on
the sftp protocol somewhere?

-Pat