posixConnect

fn posixConnect(k: *Kqueue, socket_fd: posix.socket_t, addr: *const posix.sockaddr, addr_len: posix.socklen_t) !void {
    while (true) {
        try k.checkCancel();
        switch (posix.errno(posix.system.connect(socket_fd, addr, addr_len))) {
            .SUCCESS => return,
            .INTR => continue,
            .CANCELED => return error.Canceled,
            .AGAIN => @panic("TODO"),
            .INPROGRESS => return, // Due to TCP fast open, we find out possible error later.

            .ADDRNOTAVAIL => return error.AddressUnavailable,
            .AFNOSUPPORT => return error.AddressFamilyUnsupported,
            .ALREADY => return error.ConnectionPending,
            .BADF => |err| return errnoBug(err), // File descriptor used after closed.
            .CONNREFUSED => return error.ConnectionRefused,
            .CONNRESET => return error.ConnectionResetByPeer,
            .FAULT => |err| return errnoBug(err),
            .ISCONN => |err| return errnoBug(err),
            .HOSTUNREACH => return error.HostUnreachable,
            .NETUNREACH => return error.NetworkUnreachable,
            .NOTSOCK => |err| return errnoBug(err),
            .PROTOTYPE => |err| return errnoBug(err),
            .TIMEDOUT => return error.Timeout,
            .CONNABORTED => |err| return errnoBug(err),
            .ACCES => return error.AccessDenied,
            .PERM => |err| return errnoBug(err),
            .NOENT => |err| return errnoBug(err),
            .NETDOWN => return error.NetworkDown,
            else => |err| return posix.unexpectedErrno(err),
        }
    }
}