Large Binary message isn't being sent correctly

I'm using the sync client of websockets-rs to connect to a server written in actix-web over localhost. I've got a 181KB chunk of binary that I'm requesting from my server, then sending back. I'm getting the chunk just fine from the server, but when I try to send it back the server never registers a message. Looking at wireshark, there's some packets that have 0 length. I'm sending the data like this:
let bin_message = OwnedMessage::Binary(data); client.send_message(&bin_message)
where data is a Vec<u8>.
A binary chunk of 1264 bytes went back and forth just fine. Do I need to handle the byte streaming myself? Why does this work on the receiving end and not the sending? I've verified my server with a python websocket client, I know it's working on that end.
.pcap of the traffic is attached.
dumpfile.zip

Start with the sync client's send_message path shown in the report and inspect how it frames an OwnedMessage::Binary containing a Vec. Compare the 181KB and 1264-byte cases with the attached dumpfile.zip in Wireshark, then verify that the server receives the complete binary message rather than zero-length packets.