add accumulate_peers to Node

simplifies collecting peers during a download by giving a queue of hashes to search for and a queue or peers as they are found

lbrynet/dht/node.py

@@ -236,3 +236,19 @@ class Node:
         distance = Distance(node_id)
         accumulated.sort(key=lambda peer: distance(peer.node_id))
         return accumulated[:count]
+
+    async def _accumulate_search_junction(self, search_queue: asyncio.Queue,
+                                          result_queue: asyncio.Queue):
+        try:
+            async with self.stream_peer_search_junction(search_queue) as search_junction:
+                async for peers in search_junction:
+                    if peers:
+                        result_queue.put_nowait(peers)
+        except asyncio.CancelledError:
+            return
+
+    def accumulate_peers(self, search_queue: asyncio.Queue,
+                         peer_queue: typing.Optional[asyncio.Queue] = None) -> typing.Tuple[
+                         asyncio.Queue, asyncio.Task]:
+        q = peer_queue or asyncio.Queue()
+        return q, asyncio.create_task(self._accumulate_search_junction(search_queue, q))