Command-line tool for reading TCP socket statistics from the tcpstats
kernel module on FreeBSD.

Reads fixed-size 320-byte records from /dev/tcpstats containing per-connection
TCP metrics including addresses, ports, TCP state, congestion control parameters
(cwnd, ssthresh), RTT measurements, retransmit counts, ECN statistics, and
process attribution.  Supports JSON Lines, pretty-printed JSON, and protobuf
output formats with configurable collection intervals.

Requires the tcpstats-kmod port to be installed and loaded.