build: Remove async_generator as a dependency

As Python <3.6 is no longer supported, this library is obsolete.

poetry.lock

@@ -25,17 +25,6 @@ files = [
 [package.extras]
 test = ["coverage", "mypy", "pexpect", "ruff", "wheel"]
 
-[[package]]
-name = "async-generator"
-version = "1.10"
-description = "Async generators and context managers for Python 3.5+"
-optional = false
-python-versions = ">=3.5"
-files = [
-    {file = "async_generator-1.10-py3-none-any.whl", hash = "sha256:01c7bf666359b4967d2cda0000cc2e4af16a0ae098cbffcb8472fb9e8ad6585b"},
-    {file = "async_generator-1.10.tar.gz", hash = "sha256:6ebb3d106c12920aaae42ccb6f787ef5eefdcdd166ea3d628fa8476abe712144"},
-]
-
 [[package]]
 name = "babel"
 version = "2.13.1"
@@ -1260,4 +1249,4 @@ testing = ["big-O", "jaraco.functools", "jaraco.itertools", "more-itertools", "p
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.12"
-content-hash = "4f9ec52a576209d59ea926bd2e332f5f06b4b2158c2ea348185704d21c63bd73"
+content-hash = "b578043d7c76e0f421f1e0557bbea78870cca9fb9f8713dd3b7299f08823546b"

pyproject.toml

@@ -9,7 +9,6 @@ packages = [{include = "secret_handshake"}]
 
 [tool.poetry.dependencies]
 python = "^3.12"
-async_generator = "^1.10"
 PyNaCl = "^1.5.0"
 
 [tool.poetry.group.dev.dependencies]

secret_handshake/boxstream.py

@@ -1,7 +1,6 @@
 import struct
 from asyncio import IncompleteReadError
 
-from async_generator import async_generator, yield_
 from nacl.secret import SecretBox
 
 from .util import inc_nonce, split_chunks
@@ -59,13 +58,16 @@ class UnboxStream(object):
         self.nonce = inc_nonce(inc_nonce(self.nonce))
         return body
 
-    @async_generator
+    def __aiter__(self):
-    async def __aiter__(self):
+        return self
-        while True:
+
+    async def __anext__(self):
         data = await self.read()
+
         if data is None:
-                return
+            raise StopAsyncIteration()
-            await yield_(data)
+
+        return data
 
 
 class BoxStream(object):

secret_handshake/network.py

@@ -21,8 +21,6 @@
 
 import asyncio
 
-from async_generator import async_generator, yield_
-
 from .boxstream import get_stream_pair
 from .crypto import SHSClientCrypto, SHSServerCrypto
 
@@ -48,10 +46,16 @@ class SHSDuplexStream(object):
         self.read_stream.close()
         self.is_connected = False
 
-    @async_generator
+    def __aiter__(self):
-    async def __aiter__(self):
+        return self
-        async for msg in self.read_stream:
+
-            await yield_(msg)
+    async def __anext__(self):
+        msg = await self.read()
+
+        if msg is None:
+            raise StopAsyncIteration()
+
+        return msg
 
 
 class SHSEndpoint(object):