private void ZSetSelectedProperties(cMailboxSelectedProperties pSelectedProperties, cTrace.cContext pParentContext)
                {
                    var lContext = pParentContext.NewMethod(nameof(cMailboxCacheItem), nameof(ZSetSelectedProperties), pSelectedProperties);

                    if (pSelectedProperties == null)
                    {
                        throw new ArgumentNullException(nameof(pSelectedProperties));
                    }
                    fMailboxProperties lDifferences = ZSetExists(true) | cMailboxSelectedProperties.Differences(mSelectedProperties, pSelectedProperties);

                    mSelectedProperties = pSelectedProperties;
                    mSynchroniser.InvokeMailboxPropertiesChanged(this, lDifferences, lContext);
                }
                public void ResetExists(cTrace.cContext pParentContext)
                {
                    var lContext = pParentContext.NewMethod(nameof(cMailboxCacheItem), nameof(ResetExists));

                    fMailboxProperties lProperties;

                    if (mExists == true)
                    {
                        lProperties = fMailboxProperties.exists;
                    }
                    else
                    {
                        lProperties = 0;
                    }

                    mExists             = false;
                    mListFlags          = null;
                    mStatus             = null;
                    mMailboxStatus      = null;
                    mSelectedProperties = cMailboxSelectedProperties.NeverBeenSelected;

                    mSynchroniser.InvokeMailboxPropertiesChanged(this, lProperties, lContext);
                }