Moved tai64n into sub-package

internal/tai64n/tai64.go

@@ -0,0 +1,26 @@
+package tai64n
+
+import (
+	"bytes"
+	"encoding/binary"
+	"time"
+)
+
+const TimestampSize = 12
+const base = uint64(4611686018427387914)
+
+type Timestamp [TimestampSize]byte
+
+func Now() Timestamp {
+	var tai64n Timestamp
+	now := time.Now()
+	secs := base + uint64(now.Unix())
+	nano := uint32(now.UnixNano())
+	binary.BigEndian.PutUint64(tai64n[:], secs)
+	binary.BigEndian.PutUint32(tai64n[8:], nano)
+	return tai64n
+}
+
+func (t1 Timestamp) After(t2 Timestamp) bool {
+	return bytes.Compare(t1[:], t2[:]) > 0
+}