GetAllHeaders method will initiate retrieval of headers
for all messages from the server. wodPop3 will loop through
all messages until all headers for all messages are not
received. Once it finishes, it will fire Done event.
After all headers per message are received, Received event
will be fired as well - so you can inspect headers content
immediately (or you can do it later on, depends on your
choice).
During transfer of the headers, Progress event
will be fired. It will contain invalid Total argument,
because Total specifies size of the message - not size of
headers.
No files are created on local disk when this method is
used - all headers are kept in memory.
GetAllHeaders
Method
