split Event interface into EventIdentity and EventLifecycle

Extract GetTraceId/GetPid/GetTid into EventIdentity (routing and
aggregation concerns) and Recycle into EventLifecycle (pool memory
management). Event embeds both and retains String, GetTime, Equals.
All existing implementations satisfy the composed interface unchanged.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 22 insertions, 4 deletions

diff --git a/internal/event/event.go b/internal/event/event.go
index c846e04..5fdd481 100644
--- a/internal/event/event.go
+++ b/internal/event/event.go
@@ -10,13 +10,31 @@ var poolOfEventPairs = sync.Pool{
 	New: func() any { return &Pair{} },
 }
 
-// Event is the common contract implemented by decoded syscall trace events.
-type Event interface {
-	String() string
+// EventIdentity carries the immutable identifiers of a decoded syscall event:
+// which syscall tracepoint fired (TraceId) and the kernel process/thread IDs
+// (Pid, Tid). It is embedded by Event and can be used independently wherever
+// only identity fields are needed (e.g. routing, filtering, aggregation keys).
+type EventIdentity interface {
 	GetTraceId() types.TraceId
 	GetPid() uint32
 	GetTid() uint32
+}
+
+// EventLifecycle manages the pool-backed memory lifetime of a decoded event.
+// Callers must call Recycle exactly once after the event is no longer needed
+// to return the underlying object to its sync.Pool. It is embedded by Event
+// and can be used independently wherever only lifecycle management is needed.
+type EventLifecycle interface {
+	Recycle()
+}
+
+// Event is the common contract implemented by decoded syscall trace events.
+// It composes EventIdentity (tracepoint + pid/tid) and EventLifecycle (pool
+// return) and adds timing, human-readable formatting, and equality comparison.
+type Event interface {
+	EventIdentity
+	EventLifecycle
+	String() string
 	GetTime() uint64
 	Equals(other any) bool
-	Recycle()
 }