feat: add TopicWriter class for message writing with buffering and flushing capabilities

Signed-off-by: Vladislav Polyakov <[email protected]>

Author: polRk

packages/topic/src/message.ts

@@ -6,6 +6,7 @@ export interface TopicMessage<Payload = Uint8Array> {
 	seqNo: bigint;
 	offset?: bigint;
 	payload: Payload;
+	uncompressedSize?: bigint;
 
 	createdAt?: Date;
 	writtenAt?: Date;