code: @BetaApi
    public final InstanceGroup getInstanceGroup(String instanceGroup) {
  
      GetInstanceGroupHttpRequest request =
          GetInstanceGroupHttpRequest.newBuilder().setInstanceGroup(instanceGroup).build();
      return getInstanceGroup(request);
    }
docs: Returns the specified instance group. Gets a list of available instance groups by making a
  list() request.
  
  <p>Sample code:
  
  <pre><code>
  try (InstanceGroupClient instanceGroupClient = InstanceGroupClient.create()) {
  ProjectZoneInstanceGroupName instanceGroup = ProjectZoneInstanceGroupName.of("[PROJECT]", "[ZONE]", "[INSTANCE_GROUP]");
  InstanceGroup response = instanceGroupClient.getInstanceGroup(instanceGroup.toString());
  }
  </code></pre>
  
  @param instanceGroup The name of the instance group.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails