obexd: Support for multipart response sending from phonebook-tracker

Now data are being sent with smaller parts - vcard amount for
one part is defined in VCARDS_PART_COUNT. When one part of
data is sent, then data download from tracker is stopped.
It will be resumed when phonebook_pull_read will be called again.
This is needed to start sending data from PBAP quicker - now
transfer can be started when first part of data is processed.
Previously transfer was started when all results for response
were downloaded, and (for large responses) some PBAP clients
were disconnecting due to timeout.
1 file changed