I am using a php-ews to access our EWS server. I found an example for creating a calendar event as follows:
$request = new EWSType_CreateItemType();
$request->SavedItemFolderId->DistinguishedFolderId->Id=EWSType_DistinguishedFolderIdNameType::CALENDAR;
$request->SavedItemFolderId->DistinguishedFolderId->Mailbox->EmailAddress = "dude@test.com";
...
My question: what is DistinguishedFolderId->Mailbox->EmailAddress and what does it do? I know this attribute is optional.