move first-packet processing from assembler to network thread (this was necessary to handle a corner case where the stream ends during the first udp_packet_list)
move first-packet processing from assembler to network thread (this was necessary to handle a corner case where the stream ends during the first udp_packet_list)

CHIMEFRB/ch_frb_io,CHIMEFRB/ch_frb_io,CHIMEFRB/ch_frb_io