Reading up on TCP

Closing a TCP socket with `shutdown(RD_WR)` or `close()` can cause `ECONNRESET` errors for the peer because data still in flight may be discarded before the receiver finishes reading.

An interactive guide explains browser mechanics from URL parsing to TCP connections and HTTP requests, aiming to build intuitive understanding.

TCP ensures reliable data delivery over unreliable IP by managing packet loss, congestion, and ordering, forming the backbone of HTTP, email, and SSH.