ASP.NET Core Middleware ElasticSearch Formatting

To serialize metrics in ElasticSearch document format when /metrics or /metrics-text is requested:

1. Add the App.Metrics.Formatters.ElasticSearch nuget package to your ASP.NET Core web application.
2. Configure in your Startup.cs

public class Startup
{
	public void ConfigureServices(IServiceCollection services)
	{
		services.AddMetrics()
			// .AddDefaultElasticsearchSerialization() - Enables an elasticsearach document format on the /metrics-text and /metrics endpoints respectively.
			.AddElasticsearchMetricsTextSerialization() // Enables elasticsearach document format on the /metrics-text endpoint.
			.AddElasticsearchMetricsSerialization() // Enables elasticsearach document format on the /metrics endpoint.
			.AddAsciiHealthSerialization()
			.AddHealthChecks()
			.AddMetricsMiddleware();
	}

	public void Configure(IApplicationBuilder app, ILoggerFactory loggerFactory)
	{            
		app.UseMetrics();
	}
}