Whitespace
Use 'let' for setup where possible
Whitespace
Put permissions checks in a base class
Remove unnecessary context
Use 'let' instead of local variables
Save messages to mbox files
Save modified email messages to the mbox file
Rename mbox -> mboxrd
Get the message body
Correct open type to append
Correct directory creation
Whitespace
Set permissions on each directory of the requested path from the base
Force binary encoding on message
Switch to mbox serialization
Complete 'From_' line
Ensure the message is not modified