The histogram request.
.. attribute:: histogram_query
An expression specifies a histogram request against matching
resources (for example, jobs, profiles) for searches. See [Se
archJobsRequest.histogram_queries][google.cloud.talent.v4beta
1.SearchJobsRequest.histogram_queries] and [SearchProfilesReq
uest.histogram_queries][google.cloud.talent.v4beta1.SearchPro
filesRequest.histogram_queries] for details about syntax.