write even smaller strings just like for #31 but fixes #37

This fixed #37 for me on FreeBSD 9.2-RELEASE #0 r255898. Possibly this has something to do with `sysctl` values. Possibly relevant values on my system:
```
$ sysctl net.inet.tcp.sendspace net.inet.tcp.recvspace
net.inet.tcp.sendspace: 32768
net.inet.tcp.recvspace: 65536
```