Thanks for your help.
I printed all peer_log messages. It looks like my seeder client has choked my leecher client and my leecher client has also choked my seeder client. Further they also disconnect the connection after transferring some pieces (since I found multiple handshake messages in the log). They do transfer few pieces (I am guessing after some time interval they unchoke each other). How can I make seeder and leecher make work without any choking. They should start transferring pieces as soon as request arrives.
In this regard can below setting help?
I also tried changing torrent mode to NOT auto-managed but then it doesn't download anything at all (probably because at first I set piece_priority as 0 for all pieces and then set it to 7 for the pieces that I need)
I am new to these concepts and having hard time in figuring out what is happening.