Unify conn_write_single_frame_pkt and conn_write_single_frame_handshake_pkt
Unify conn_write_single_frame_pkt and conn_write_single_frame_handshake_pkt

ngtcp2/ngtcp2,nickfajones/ngtcp2,nickfajones/ngtcp2,ngtcp2/ngtcp2,ngtcp2/ngtcp2,nickfajones/ngtcp2