AndProcess will walk the message parts tree of a message (or a part of a message) and call the given Processor function for each part found.

AndProcessMultipart is identical to AndProcess(), except that the processor function is only applied to parts that are multipart.

AndProcessOpaque is identical to AndProcess(), except that the Processor function is only applied to parts that are not multipart.

AndTransform will walk each of the parts of the given message.Part in depth-first order.

Processor is a callback that can be passed to the AndProcess() function to do any kind of generic processing of a message and its sub-parts.

Transformer is a tool for aiding with advanced transformation of email.