private EmbeddedChannel createChannel() {
    return new EmbeddedChannel(new HealthCheckHandler(restServerState, new NettyMetrics(new MetricRegistry())),
        new EchoMethodHandler());
  }
Creates an {@link EmbeddedChannel} that incorporates an instance of {@link HealthCheckHandler}
and {@link EchoMethodHandler}.
@return an {@link EmbeddedChannel} that incorporates an instance of {@link HealthCheckHandler}
and {@link EchoMethodHandler}.
ambry-rest/src/test/java/com/github/ambry/rest/HealthCheckHandlerTest.java