( resource imap_stream, int msg_number, string part_number [, int options] )
This function causes a fetch of a particular section of the body
of the specified messages as a text string and returns that text
string. The section specification is a string of integers
delimited by period which index into a body part list as per the
IMAP4 specification. Body parts are not decoded by this function.
The options for
imap_fetchbody() is a bitmask with one or more
of the following:
FT_UID - The msg_number is a UID
FT_PEEK - Do not set the \Seen flag if
not already set
FT_INTERNAL - The return string is in
internal format, will not canonicalize to CRLF.
See also: imap_fetchstructure().