Clarify thread-safety of Socket.Connected (#4493)

* Clarify thread-safety of Socket.Connected

* update wording

Author: tmds

xml/System.Net.Sockets/Socket.xml

@@ -3845,7 +3845,7 @@ This method populates the <xref:System.Net.Sockets.Socket> instance with data ga
           <format type="text/markdown"><![CDATA[  
 
 ## Remarks  
- The `Connected` property gets the connection state of the <xref:System.Net.Sockets.Socket> as of the last I/O operation. When it returns `false`, the <xref:System.Net.Sockets.Socket> was either never connected, or is no longer connected.  
+ The `Connected` property gets the connection state of the <xref:System.Net.Sockets.Socket> as of the last I/O operation. When it returns `false`, the <xref:System.Net.Sockets.Socket> was either never connected, or is no longer connected. `Connected` is not thread-safe; it may return `true` after an operation is aborted when the <xref:System.Net.Sockets.Socket> is disconnected from another thread.
 
  The value of the <xref:System.Net.Sockets.Socket.Connected%2A> property reflects the state of the connection as of the most recent operation. If you need to determine the current state of the connection, make a nonblocking, zero-byte Send call. If the call returns successfully or throws a WAEWOULDBLOCK error code (10035), then the socket is still connected; otherwise, the socket is no longer connected.