Implemented do_stem_stream to stem blocks for dandelion++

src/gossip/client/dandelionstem/stemstream.py

@@ -0,0 +1,25 @@
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from queue import Queue
+    import socket
+    from ...dandelion import DandelionPhase
+
+    from onionrblocks import Block
+
+
+async def do_stem_stream(
+        peer_socket: 'socket.socket',
+        block_queue: "Queue[Block]",
+        d_phase: 'DandelionPhase'):
+    remaining_time = d_phase.remaining_time()
+    my_phase_id = d_phase.phase_id
+
+    with peer_socket:
+        while remaining_time > 5 and my_phase_id == d_phase.phase_id:
+            # Primary client component that communicate's with gossip.server.acceptstem
+            remaining_time = d_phase.remaining_time()
+            bl: 'Block' = block_queue.get(block=True, timeout=remaining_time)
+            peer_socket.sendall(bl.id)
+            peer_socket.sendall(len(bl.raw))
+            peer_socket.sendall(bl.raw)