feat(sdk): add util module with collect helper func; update spin-kv example to suit

Signed-off-by: Vaughn Dice <vdice@akamai.com>
Co-authored-by: Joel Dice <joel.dice@akamai.com>

Author: vdice

docs/v4/index.html

@@ -1,31 +1,19 @@
-from typing import TypeVar, Tuple, List
-from componentize_py_types import Result, Err
-from componentize_py_async_support.streams import StreamReader
-from componentize_py_async_support.futures import FutureReader
-from spin_sdk import http, key_value
+from spin_sdk import http, key_value, util
 from spin_sdk.http import Request, Response
 from spin_sdk.key_value import Store
 
 class WasiHttpHandler030Rc20260315(http.Handler):
     async def handle_request(self, request: Request) -> Response:
         with await key_value.open_default() as a:
             await a.set("test", bytes("hello world!", "utf-8"))
-            print(await get_keys(a))
+            print(await util.collect(await a.get_keys()))
             print(await a.exists("test"))
             print(await a.get("test"))
             await a.delete("test")
-            print(await get_keys(a))
+            print(await util.collect(await a.get_keys()))
 
         return Response(
             200,
             {"content-type": "text/plain"},
             bytes("Hello from Python!", "utf-8")
         )
-
-async def get_keys(store: Store) -> list[str]:
-    stream, future = await store.get_keys()
-    with stream, future:
-        keys = []
-        while not stream.writer_dropped:
-            keys += await stream.read(max_count=100)
-        return keys

docs/v4/util.html

@@ -0,0 +1,26 @@
+"""Module for general-purpose utility functions"""
+
+from typing import TypeVar, Tuple, List
+from componentize_py_types import Result, Err
+from componentize_py_async_support.streams import StreamReader
+from componentize_py_async_support.futures import FutureReader
+
+T = TypeVar('T')
+E = TypeVar('E')
+
+async def collect(tuple: Tuple[StreamReader[T], FutureReader[Result[None, E]]]) -> List[T]:
+    """
+    Collect all items from the StreamReader portion of the provided Tuple and return them in a List,
+    verifying the FutureReader result upon stream completion and, if it is error, raising it as an exception.
+    """
+    stream = tuple[0]
+    future = tuple[1]
+    collected = []
+    with stream, future:
+        while not stream.writer_dropped:
+            collected += await stream.read(128)
+        result = await future.read()
+        if isinstance(result, Err):
+            raise result
+        else:
+            return collected