bin/39712: scp(1) shows negative values for 0 bytes files

[njoly%pasteur.fr@localhost]

>Number:         39712
>Category:       bin
>Synopsis:       scp(1) shows negative values for 0 bytes files
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Oct 07 16:15:00 +0000 2008
>Originator:     Nicolas Joly
>Release:        NetBSD 4.99.72
>Organization:
Biological Software and Databanks.
Institut Pasteur, Paris.
>Environment:
System: NetBSD lanfeust.sis.pasteur.fr 4.99.72 NetBSD 4.99.72 (LANFEUST) #76: 
Mon Oct 6 12:50:58 CEST 2008 
njoly%lanfeust.sis.pasteur.fr@localhost:/local/src/NetBSD/obj.amd64/sys/arch/amd64/compile/LANFEUST
 amd64
Architecture: x86_64
Machine: amd64
>Description:
scp(1) can report negative tranfert rates for 0 bytes files.

njoly@lanfeust [~]> ls -l {embl,imgt}.log
-rw-r--r--  1 njoly  users  52281 Aug 29 16:24 embl.log
-rw-r--r--  1 njoly  users      0 Mar 11  2008 imgt.log

njoly@lanfeust [~]> scp {embl,imgt}.log medusa.sis.pasteur.fr:/tmp
embl.log                               100%   51KB  51.1KB/s  51.1KB/s   00:00
imgt.log                               100%    0     0.0KB/s -51.0KB/s   00:00

This does not occurs when the empty file is processed first.

njoly@lanfeust [~]> scp {imgt,embl}.log medusa.sis.pasteur.fr:/tmp
imgt.log                               100%    0     0.0KB/s   0.0KB/s   00:00
embl.log                               100%   51KB  51.1KB/s  51.1KB/s   00:00

>How-To-Repeat:
Use scp(1) to transfert 0 bytes files.
>Fix: