The refresh API allows to explicitly refresh one or more index, making all operations performed since the last refresh available for search. The (near) real-time capabilities depends on the index engine used. For example, the robin one requires refresh to be called, but by default a refresh is scheduled periodically.

var r = this.ConnectedClient.Refresh();

var r = this.ConnectedClient.Refresh("index");
r = this.ConnectedClient.Refresh(new [] {"index4", "index2" });

var r = this.ConnectedClient.Refresh<ElasticSearchProject>();