Getting TimeTracking Array together when I get Issues.

Hello.

My current scenario is as below.

========================================================================================
1. Getting issues from Server
Query: api/issues?query=state:%20open%20-feature&fields=created,updated,tags(name),fields(id,projectCustomField(field(name)),value(name)),reporter(fullName),updater(fullName),summary,numberInProject,comments(author(fullName),created)

2. Getting timeTrackings on each {issueId}
Query: /api/issues/{issueID}/timeTracking/workItems?fields=author(id,name),creator(id,name),date,duration(id,minutes,presentation),id,name,text,type(id,name)

3. Attaching timeTrackings array to a single Issue array, when matches.
========================================================================================

The above solution works, but due to many GET request on the 2nd phase, the performance is totally bad.
I think the best way to solve this scenario is that to add an timeTracking attribute to issues as comments(
Iterable<IssueComment>)
Could you kindly let me know there is any possible solution now ?