libnspv make delays when sending messages, apparently because of buffering

[dimxy]

Tests show that requests via libnspv might perform with delay of several seconds.
Libnspv uses libevent2 library to send/receive messages over net. It looks like libevent2 does buffering internally before actual sending.
I search or something like a flush feature but according to this it is not possible yet:

Currently (as of Libevent 2.0.5-beta), bufferevent_flush() is only implemented for some bufferevent types. In particular, socket-based bufferevents don’t have it. http://www.wangafu.net/~nickm/libevent-book/Ref6_bufferevent.html

Maybe we need to contact libevent2 devs to get more info.