code: @BetaApi
    public final InstanceGroup getRegionInstanceGroup(String instanceGroup) {
  
      GetRegionInstanceGroupHttpRequest request =
          GetRegionInstanceGroupHttpRequest.newBuilder().setInstanceGroup(instanceGroup).build();
      return getRegionInstanceGroup(request);
    }
docs: Returns the specified instance group resource.
  
  <p>Sample code:
  
  <pre><code>
  try (RegionInstanceGroupClient regionInstanceGroupClient = RegionInstanceGroupClient.create()) {
  ProjectRegionInstanceGroupName instanceGroup = ProjectRegionInstanceGroupName.of("[PROJECT]", "[REGION]", "[INSTANCE_GROUP]");
  InstanceGroup response = regionInstanceGroupClient.getRegionInstanceGroup(instanceGroup.toString());
  }
  </code></pre>
  
  @param instanceGroup Name of the instance group resource to return.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails