✨ feat: Add streaming support (#125)

This adds:
- [x] Keyboard and mouse handling on the frontend
- [x] Video and audio streaming from the backend to the frontend
- [x] Input server that works with Websockets

Update - 17/11
- [ ] Master docker container to run this
- [ ] Steam runtime
- [ ] Entrypoint.sh

---------

Co-authored-by: Kristian Ollikainen <14197772+DatCaptainHorse@users.noreply.github.com>
Co-authored-by: Kristian Ollikainen <DatCaptainHorse@users.noreply.github.com>

packages/relay/internal/latency.go

@@ -0,0 +1,114 @@
+package relay
+
+import (
+	"fmt"
+	"time"
+)
+
+type TimestampEntry struct {
+	Stage string `json:"stage"`
+	Time  string `json:"time"` // ISO 8601 string
+}
+
+// LatencyTracker provides a generic structure for measuring time taken at various stages in message processing.
+// It can be embedded in message structs for tracking the flow of data and calculating round-trip latency.
+type LatencyTracker struct {
+	SequenceID string            `json:"sequence_id"`
+	Timestamps []TimestampEntry  `json:"timestamps"`
+	Metadata   map[string]string `json:"metadata,omitempty"`
+}
+
+// NewLatencyTracker initializes a new LatencyTracker with the given sequence ID
+func NewLatencyTracker(sequenceID string) *LatencyTracker {
+	return &LatencyTracker{
+		SequenceID: sequenceID,
+		Timestamps: make([]TimestampEntry, 0),
+		Metadata:   make(map[string]string),
+	}
+}
+
+// AddTimestamp adds a new timestamp for a specific stage
+func (lt *LatencyTracker) AddTimestamp(stage string) {
+	lt.Timestamps = append(lt.Timestamps, TimestampEntry{
+		Stage: stage,
+		// Ensure extremely precise UTC RFC3339 timestamps (down to nanoseconds)
+		Time: time.Now().UTC().Format(time.RFC3339Nano),
+	})
+}
+
+// TotalLatency calculates the total latency from the earliest to the latest timestamp
+func (lt *LatencyTracker) TotalLatency() (int64, error) {
+	if len(lt.Timestamps) < 2 {
+		return 0, nil // Not enough timestamps to calculate latency
+	}
+
+	var earliest, latest time.Time
+	for _, ts := range lt.Timestamps {
+		t, err := time.Parse(time.RFC3339, ts.Time)
+		if err != nil {
+			return 0, err
+		}
+		if earliest.IsZero() || t.Before(earliest) {
+			earliest = t
+		}
+		if latest.IsZero() || t.After(latest) {
+			latest = t
+		}
+	}
+
+	return latest.Sub(earliest).Milliseconds(), nil
+}
+
+// PainPoints returns a list of stages where the duration exceeds the given threshold.
+func (lt *LatencyTracker) PainPoints(threshold time.Duration) []string {
+	var painPoints []string
+	var lastStage string
+	var lastTime time.Time
+
+	for _, ts := range lt.Timestamps {
+		stage := ts.Stage
+		t := ts.Time
+		if lastStage == "" {
+			lastStage = stage
+			lastTime, _ = time.Parse(time.RFC3339, t)
+			continue
+		}
+
+		currentTime, _ := time.Parse(time.RFC3339, t)
+		if currentTime.Sub(lastTime) > threshold {
+			painPoints = append(painPoints, fmt.Sprintf("%s -> %s", lastStage, stage))
+		}
+
+		lastStage = stage
+		lastTime = currentTime
+	}
+	return painPoints
+}
+
+// StageLatency calculates the time taken between two specific stages.
+func (lt *LatencyTracker) StageLatency(startStage, endStage string) (time.Duration, error) {
+	startTime, endTime := "", ""
+	for _, ts := range lt.Timestamps {
+		if ts.Stage == startStage {
+			startTime = ts.Time
+		}
+		if ts.Stage == endStage {
+			endTime = ts.Time
+		}
+	}
+
+	if startTime == "" || endTime == "" {
+		return 0, fmt.Errorf("missing timestamps for stages: %s -> %s", startStage, endStage)
+	}
+
+	start, err := time.Parse(time.RFC3339, startTime)
+	if err != nil {
+		return 0, err
+	}
+	end, err := time.Parse(time.RFC3339, endTime)
+	if err != nil {
+		return 0, err
+	}
+
+	return end.Sub(start), nil
+}