Fix a couple of issues with Python 3.14

This commit fixes an issue related to lazy evaluation of annotations
in Python 3.14.  Thanks go to Georg Sauthoff for finding and
reporting this issue.

This commit also fixes a deprecation warning for the function
asyncio.iscoroutinefunction(), switching to use the version in
the inspect module.

asyncssh/misc.py

@@ -466,17 +466,18 @@ def update(self, **kwargs: object) -> None:
 class _RecordMeta(type):
     """Metaclass for general-purpose record type"""
 
+    __slots__: Dict[str, object] = {}
+
     def __new__(mcs: Type['_RecordMeta'], name: str, bases: Tuple[type, ...],
                 ns: Dict[str, object]) -> '_RecordMeta':
+        cls = cast(_RecordMeta, super().__new__(mcs, name, bases, ns))
+
         if name != 'Record':
-            fields = cast(Mapping[str, str],
-                          ns.get('__annotations__', {})).keys()
+            fields = cast(Mapping[str, str], cls.__annotations__.keys())
             defaults = {k: ns.get(k) for k in fields}
+            cls.__slots__ = defaults
 
-            ns = {k: v for k, v in ns.items() if k not in fields}
-            ns['__slots__'] = defaults
-
-        return cast(_RecordMeta, super().__new__(mcs, name, bases, ns))
+        return cls
 
 
 class Record(metaclass=_RecordMeta):

asyncssh/process.py

@@ -928,7 +928,7 @@ def pipe_factory() -> _PipeReader:
                 file = source
 
             if hasattr(file, 'read') and \
-                    (asyncio.iscoroutinefunction(file.read) or
+                    (inspect.iscoroutinefunction(file.read) or
                      inspect.isgeneratorfunction(file.read)):
                 reader = _AsyncFileReader(self, cast(_AsyncFileProtocol, file),
                                           bufsize, datatype, self._encoding,
@@ -997,7 +997,7 @@ def pipe_factory() -> _PipeWriter:
                 needs_close = recv_eof
 
             if hasattr(file, 'write') and \
-                    (asyncio.iscoroutinefunction(file.write) or
+                    (inspect.iscoroutinefunction(file.write) or
                      inspect.isgeneratorfunction(file.write)):
                 writer = _AsyncFileWriter(
                     self, cast(_AsyncFileProtocol, file), needs_close,