The IsBlocked property returns True if the control is
blocked performing an operation. If the IsBlocked property
returns False, this means there are no blocking operations on the
current thread at that time. If the property returns True, this tells
you that you can't proceed with a socket operation. However, if the
property returns False this does not guarantee that the next socket
operation will not fail with a swErrorOperationWouldBlock or
swErrorOperationInProgress error. The application should treat
these errors as recoverable, and should be prepared to retry
operations that result in them.
Note that this property will return True if there is any
blocking operation being performed by the application, regardless of
whether the control is responsible for the blocking operation or
not.