code: public boolean isConnected() {
  
          // if we haven't fully read the incoming message then this
          // connection should still be valid
          if (!this.myInterface.isIncomingMessageFullyRead()) {
              return true;
          }
  
          try {
              // if the immediate TCP read works then this connection is
              // still connected
              if (null == this.myInterface.getTSC().getReadInterface().getBuffer()) {
                  // no read buffer currently exists, use JITAllocate
                  this.myInterface.getTSC().getReadInterface().setJITAllocateSize(this.myInterface.getHttpConfig().getIncomingHdrBufferSize());
              }
              this.myInterface.getTSC().getReadInterface().read(0, 0);
              return true;
          } catch (IOException e) {
              // No FFDC required
  
              // if an exception happens, then this connection is dead
              return false;
          }
      }
docs: Query whether this outbound link is still actively connected to the
  target host. If this returns true, then the link is expected to be
  still valid for continued use. If this returns false, then the
  connection is inactive and the caller must close down the connection
  and not send/read anymore data, as any attempts to do so will result
  in errors.
  
  @return boolean