message-mail
message-mail is an interactive autoloaded compiled Lisp function in `message.el
'.
(message-mail &optional TO SUBJECT OTHER-HEADERS CONTINUE SWITCH-FUNCTION YANK-ACTION SEND-ACTIONS RETURN-ACTION &rest IGNORED)
Start editing a mail message to be sent.
OTHER-HEADERS is an alist of header/value pairs. CONTINUE says whether
to continue editing a message already being composed. SWITCH-FUNCTION
is a function used to switch to and display the mail buffer.