Checks the overall permission state of the System.Net.WebPermission.
true if the System.Net.WebPermission was created with the System.Security.Permissions.PermissionState.Unrestricted System.Security.Permissions.PermissionState; otherwise, false.
If System.Net.WebPermission is System.Security.Permissions.PermissionState.Unrestricted, then the target class can use all URIs. Otherwise, specific permission must be given for any URI you want to use with the target class.
Use WebPermission.AddPermission(NetworkAccess, string) to add a URI and specify its permissions.