/**
* @brief Opens a client socket to a remote host.
* @param host: who you want to connect to
* @param port: where you want to connect to on this host
* @param buf_size: size of the buffer (in bytes) on the socket (for TCP sockets only). If 0, a sain default is used (32k, but may change)
* @param measurement: whether this socket is meant to convey measurement (if you don't know, use 0 to exchange regular messages)
/**
* @brief Opens a client socket to a remote host.
* @param host: who you want to connect to
* @param port: where you want to connect to on this host
* @param buf_size: size of the buffer (in bytes) on the socket (for TCP sockets only). If 0, a sain default is used (32k, but may change)
* @param measurement: whether this socket is meant to convey measurement (if you don't know, use 0 to exchange regular messages)