IContentHandler.Preamble Method 

Called for the preamble (whatever comes before the first body part) of a multipart/* entity.

void Preamble(
   Stream inputStream
);

Parameters

inputStream
used to get the contents of the preamble.

Exceptions

Exception Type Condition
IOException should be thrown on I/O errors.

See Also

IContentHandler Interface | NI.Email.Mime Namespace