Adding global fields to the beeline

beelineinit.go

	client, err := libhoney.NewClient(libhoney.ClientConfig{
		APIHost:      url,
		APIKey:       writeKey,
		Dataset:      dataset,
		Transmission: &transmission.Honeycomb{
			MaxBatchSize:           libhoney.DefaultMaxBatchSize,
			MaxConcurrentBatches:   libhoney.DefaultMaxConcurrentBatches,
			PendingWorkCapacity:    libhoney.DefaultPendingWorkCapacity,
			BatchTimeout:           libhoney.DefaultBatchTimeout,
			DisableGzipCompression: b.DisableGzipCompression,
		},
		SampleRate:   b.SampleRate,
	})

	config := beeline.Config{
		ServiceName: b.ServiceName,
		SampleRate:  b.SampleRate,
		Client:      client,
	}
	beeline.Init(config)

	client.addField("global.os_version", osVersion)
	client.addField("global.build_id", BuildID)

And are the two SampleRates redundant?