Annotations are not displayed when time set to a full day/week/month...

[primary1]

Annotations are not displayed for last hour/day/week/month if "To" in range is set to a full hour/day/week/month.
Examples:
From: now/d To: now/d
From now-2d/d To: now-1d/d
From: now/h To: now/h
From: 2019-02-18 09:00:00 To: now/d

Looks like "to" value is converted incorrectly to the beginning of the hour/day/week/month instead of the end of it.

Example from http://play.grafana-zabbix.org with screenshot and network data:

From=1550476800000 (date: 2019-02-18 09:00:00)
To=now%2Fd (date: 2019-02-19 23:59:59, timestamp: 1550617199999)

Request headers:
GET http://play.grafana-zabbix.org/api/annotations?dashboardId=8&from=1550476800000&to=1550617199999 HTTP/1.1 Host: play.grafana-zabbix.org Proxy-Connection: keep-alive Accept: application/json, text/plain, */* X-Grafana-Org-Id: 2 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36 Referer: http://play.grafana-zabbix.org/d/000000008/annotations?orgId=2&from=1550476800000&to=now%2Fd Accept-Encoding: gzip, deflate Accept-Language: pl,fr;q=0.9,en-US;q=0.8,en;q=0.7 Cookie: grafana_sess=dc517dc4c9a3e8b6

Request payload:
{"jsonrpc":"2.0","method":"event.get","params":{"output":"extend","time_from":1550476800,"time_till":1550530800,"objectids":["13675","13681","14098","14103","14108","13682"],"select_acknowledges":"extend","selectHosts":"extend","value":1},"id":1,"auth":"838267e1e0dd0a360fbb0a36df6e61b6"}

As you can see, "time_till":1550530800 (date: 2019-02-19 00:00:00) is incorrect. It should be 1550617199.

Tested on different Grafana and Zabbix plugin versions:

Grafana	Zabbix	Grafana-Zabbix Plugin
5.3.4	3.4.14	3.9.1
5.3.4	3.4.14	3.10.0
5.4.3	3.4.14	3.10.0

[alexanderzobnin]

Yes, confirmed. Looks like plugin calculates wrong time range for this kind of interval.