Why not use STAP-A in RtpPacketizerH265

[getroot]

Looking at the RtpPacketizerH265::GeneratePackets function, you can see code like this:

if (fragment_len> single_packet_capacity)
     {
       PacketizeFu(i);
       ++i;
     }
     else
     {
       Packetize Single Nalu(i);
       ++i;
     }

I think it's better to use PacketizeAp instead of PacketizeSingleNalu here. Is this intended? Or is it a mistake? I wonder why the H265Packetizer uses SingleNalu instead of STAB-A if it is intended to waste the remaining space of a RTP packet.