VOL-1868 move simulated onu from voltha-go to voltha-simonu-adapter

Sourced from voltha-go commit 251a11c0ffe60512318a644cd6ce0dc4e12f4018

Change-Id: Iab179bc2f3dd772ed7f488d1c03d1a84ba75e874
diff --git a/vendor/github.com/armon/go-metrics/start.go b/vendor/github.com/armon/go-metrics/start.go
new file mode 100644
index 0000000..32a28c4
--- /dev/null
+++ b/vendor/github.com/armon/go-metrics/start.go
@@ -0,0 +1,141 @@
+package metrics
+
+import (
+	"os"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/hashicorp/go-immutable-radix"
+)
+
+// Config is used to configure metrics settings
+type Config struct {
+	ServiceName          string        // Prefixed with keys to separate services
+	HostName             string        // Hostname to use. If not provided and EnableHostname, it will be os.Hostname
+	EnableHostname       bool          // Enable prefixing gauge values with hostname
+	EnableHostnameLabel  bool          // Enable adding hostname to labels
+	EnableServiceLabel   bool          // Enable adding service to labels
+	EnableRuntimeMetrics bool          // Enables profiling of runtime metrics (GC, Goroutines, Memory)
+	EnableTypePrefix     bool          // Prefixes key with a type ("counter", "gauge", "timer")
+	TimerGranularity     time.Duration // Granularity of timers.
+	ProfileInterval      time.Duration // Interval to profile runtime metrics
+
+	AllowedPrefixes []string // A list of metric prefixes to allow, with '.' as the separator
+	BlockedPrefixes []string // A list of metric prefixes to block, with '.' as the separator
+	AllowedLabels   []string // A list of metric labels to allow, with '.' as the separator
+	BlockedLabels   []string // A list of metric labels to block, with '.' as the separator
+	FilterDefault   bool     // Whether to allow metrics by default
+}
+
+// Metrics represents an instance of a metrics sink that can
+// be used to emit
+type Metrics struct {
+	Config
+	lastNumGC     uint32
+	sink          MetricSink
+	filter        *iradix.Tree
+	allowedLabels map[string]bool
+	blockedLabels map[string]bool
+	filterLock    sync.RWMutex // Lock filters and allowedLabels/blockedLabels access
+}
+
+// Shared global metrics instance
+var globalMetrics atomic.Value // *Metrics
+
+func init() {
+	// Initialize to a blackhole sink to avoid errors
+	globalMetrics.Store(&Metrics{sink: &BlackholeSink{}})
+}
+
+// DefaultConfig provides a sane default configuration
+func DefaultConfig(serviceName string) *Config {
+	c := &Config{
+		ServiceName:          serviceName, // Use client provided service
+		HostName:             "",
+		EnableHostname:       true,             // Enable hostname prefix
+		EnableRuntimeMetrics: true,             // Enable runtime profiling
+		EnableTypePrefix:     false,            // Disable type prefix
+		TimerGranularity:     time.Millisecond, // Timers are in milliseconds
+		ProfileInterval:      time.Second,      // Poll runtime every second
+		FilterDefault:        true,             // Don't filter metrics by default
+	}
+
+	// Try to get the hostname
+	name, _ := os.Hostname()
+	c.HostName = name
+	return c
+}
+
+// New is used to create a new instance of Metrics
+func New(conf *Config, sink MetricSink) (*Metrics, error) {
+	met := &Metrics{}
+	met.Config = *conf
+	met.sink = sink
+	met.UpdateFilterAndLabels(conf.AllowedPrefixes, conf.BlockedPrefixes, conf.AllowedLabels, conf.BlockedLabels)
+
+	// Start the runtime collector
+	if conf.EnableRuntimeMetrics {
+		go met.collectStats()
+	}
+	return met, nil
+}
+
+// NewGlobal is the same as New, but it assigns the metrics object to be
+// used globally as well as returning it.
+func NewGlobal(conf *Config, sink MetricSink) (*Metrics, error) {
+	metrics, err := New(conf, sink)
+	if err == nil {
+		globalMetrics.Store(metrics)
+	}
+	return metrics, err
+}
+
+// Proxy all the methods to the globalMetrics instance
+func SetGauge(key []string, val float32) {
+	globalMetrics.Load().(*Metrics).SetGauge(key, val)
+}
+
+func SetGaugeWithLabels(key []string, val float32, labels []Label) {
+	globalMetrics.Load().(*Metrics).SetGaugeWithLabels(key, val, labels)
+}
+
+func EmitKey(key []string, val float32) {
+	globalMetrics.Load().(*Metrics).EmitKey(key, val)
+}
+
+func IncrCounter(key []string, val float32) {
+	globalMetrics.Load().(*Metrics).IncrCounter(key, val)
+}
+
+func IncrCounterWithLabels(key []string, val float32, labels []Label) {
+	globalMetrics.Load().(*Metrics).IncrCounterWithLabels(key, val, labels)
+}
+
+func AddSample(key []string, val float32) {
+	globalMetrics.Load().(*Metrics).AddSample(key, val)
+}
+
+func AddSampleWithLabels(key []string, val float32, labels []Label) {
+	globalMetrics.Load().(*Metrics).AddSampleWithLabels(key, val, labels)
+}
+
+func MeasureSince(key []string, start time.Time) {
+	globalMetrics.Load().(*Metrics).MeasureSince(key, start)
+}
+
+func MeasureSinceWithLabels(key []string, start time.Time, labels []Label) {
+	globalMetrics.Load().(*Metrics).MeasureSinceWithLabels(key, start, labels)
+}
+
+func UpdateFilter(allow, block []string) {
+	globalMetrics.Load().(*Metrics).UpdateFilter(allow, block)
+}
+
+// UpdateFilterAndLabels set allow/block prefixes of metrics while allowedLabels
+// and blockedLabels - when not nil - allow filtering of labels in order to
+// block/allow globally labels (especially useful when having large number of
+// values for a given label). See README.md for more information about usage.
+func UpdateFilterAndLabels(allow, block, allowedLabels, blockedLabels []string) {
+	globalMetrics.Load().(*Metrics).UpdateFilterAndLabels(allow, block, allowedLabels, blockedLabels)
+}