Comments/questions:
* The term character should not be used. Use octet. Character has
specific meaning for those that deal with character encodings (e.g.
UTF-8, ISO-2022-JP).
For example, replace "octet characters" with "octets".
* Why is step (2) needed?
* Why does (4) only apply to the beginning of the body part and not
the end? I know of real-world cases where dropping LWSP at the
end of the body part is needed. I'm not aware of any concerns
about the beginning of a body part.
It seems (4) could be stated more concisely as follows:
All LWSP at the beginning and end of the body part is dropped.
--ewh