neither SHARE_HISTORY, INC_APPEND_HISTORY, INC_APPEND_HISTORY_TIME is good
enough in my use case so i want to do the work in zshaddhistory:

unsetopt SHARE_HISTORY

zshaddhistory(){
local COMMAND_STR=${1%%$'\n'}
print -r -- "$COMMAND_STR" >> $HISTFILE
# from http://zsh.sourceforge.net/Doc/Release/Functions.html to avoid
writing to $HISTFILE
return 2
}

but this results in duplicate entries to $HISTFILE

how do I prevent the automatic writing to $HISTFILE?