zabbix_sender item value stacking

[bhowerter]

I don't understand what the 2.0 manual means when it says:
"Since Zabbix 1.8.4, zabbix_sender realtime sending scenarios have been improved to gather multiple values passed to it in close succession and send them to the server in a single connection. A value that is not further apart from the previous value than 0.2 seconds can be put in the same stack, but maximum pooling time still is 1 second."

Isn't zabbix_sender a synchronous non-daemon program that sends the data as soon as it runs? How can it make a single connection across multiple invocations?

[bhowerter]

Zabbix_sender --real-time sends values as they are received

Brad, if you use the --real-time option (which is also -r), coupled with --input_file - (causing input to be read from Standard Input), then zabbix_sender will cache values this way, for up to one second. (Source: zabbix_sender.c).