feedmail-buffer-eating-function

feedmail-buffer-eating-function is a variable defined in `feedmail.el'.
Its value is

feedmail-buffer-to-binmail

• This variable may be risky if used as a file-local variable.

Documentation:
Function used to send the prepped buffer to a subprocess.
The function's three (mandatory) arguments are: (1) the buffer
containing the prepped message; (2) a buffer where errors should be
directed; and (3) a list containing the addresses individually as
strings. Popular choices for this are `feedmail-buffer-to-binmail',
`feedmail-buffer-to-smtpmail', `feedmail-buffer-to-sendmail', and
`feedmail-buffer-to-smtp'. If you use the sendmail form, you probably
want to set `feedmail-nuke-bcc' and/or `feedmail-nuke-resent-bcc to nil'.
If you use the binmail form, check the value of `feedmail-binmail-template'.

You can customize this variable.