QT QAbstractSocket类

QAbstractSocket is the base class for QTcpSocket and QUdpSocket and contains all common functionality of these two classes
是QTcpSocket and QUdpSocket的基类；

1.enum QAbstractSocket::SocketType：
QAbstractSocket::TcpSocket
QAbstractSocket::UdpSocket
QAbstractSocket::SctpSocket
QAbstractSocket::UnknownSocketType

2.void QAbstractSocket::abort()
立即断开当前套接字

3.bool QAbstractSocket::atEnd() const
Returns true if no more data is currently available for reading; otherwise returns false.
This function is most commonly used when reading data from the socket in a loop. For example:

 void SocketClass::readyReadSlot()
 {
     while (!socket.atEnd()) {