fmsg: implement suspend in writer

This removes the requirement to call fmsg.Exit on every exit path, and enables direct use of the "log" package. However, fmsg.BeforeExit is still encouraged when possible to catch exit on suspended output.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/state/multi.go

@@ -85,17 +85,17 @@ func (s *multiStore) List() ([]int, error) {
 	for _, e := range entries {
 		// skip non-directories
 		if !e.IsDir() {
-			fmsg.VPrintf("skipped non-directory entry %q", e.Name())
+			fmsg.Verbosef("skipped non-directory entry %q", e.Name())
 			continue
 		}
 
 		// skip non-numerical names
 		if v, err := strconv.Atoi(e.Name()); err != nil {
-			fmsg.VPrintf("skipped non-aid entry %q", e.Name())
+			fmsg.Verbosef("skipped non-aid entry %q", e.Name())
 			continue
 		} else {
 			if v < 0 || v > 9999 {
-				fmsg.VPrintf("skipped out of bounds entry %q", e.Name())
+				fmsg.Verbosef("skipped out of bounds entry %q", e.Name())
 				continue
 			}