The remaining leaks are in hS3. The leak with encryption was worked around by the use of the temp file. (And was probably originally caused by gpgCipherHandle sparking a thread which kept a reference to the start of the byte string.)
Provide file size to new version of hS3.
Finished applying to S3 the change that fixed the memory leak in bup, but it didn't seem to help S3.. with encryption it still grows to 2x file size.