Returns a pointer to the recipient list for the currently open item.
See IExchExtCallback : IUnknown.
HRESULT GetRecipients(
LPADRLIST FAR * lppal
);
The recipient list is returned in a MAPI ADRLIST structure.
This method is called in the following contexts:
EECONTEXT_SENDNOTEMESSAGE
EECONTEXT_READNOTEMESSAGE
EECONTEXT_SENDPOSTMESSAGE
EECONTEXT_READPOSTMESSAGE
EECONTEXT_READREPORTMESSAGE
EECONTEXT_SENDRESENDMESSAGE
IExchExtCallback::SetRecipients