[tcpdump-workers] --immediate-mode in combination with -U

Hi, would you consider adding a mention of the --immediate-mode to the -U option in the manpage? For someone who is not familiar with how the packets are buffered before they are passed to tcpdump, it might not be obvious to use --immediate-mode together with -U to get the same behavior when writi

[tcpdump-workers] -G and -C options

Hi, with -C option, the manpage says "Note that when used with -Z option (enabled by default), privileges  are  dropped  before opening first savefile." So when I run tcpdump as root like this: # tcpdump -n -i eth0 -s 0 -C 3 -w /opt/tcpdump%F--%T.pcap I immediately get 'Permission' denied error