+ void (*log)(Plug p, int type, SockAddr addr, int port,
+ const char *error_msg, int error_code);
+ /*
+ * Passes the client progress reports on the process of setting
+ * up the connection.
+ *
+ * - type==0 means we are about to try to connect to address
+ * `addr' (error_msg and error_code are ignored)
+ * - type==1 means we have failed to connect to address `addr'
+ * (error_msg and error_code are supplied). This is not a
+ * fatal error - we may well have other candidate addresses
+ * to fall back to. When it _is_ fatal, the closing()
+ * function will be called.
+ */