docs: Python sync client zero-copy buffers for mget

src/content/docs/how-to/synchronous-connection.mdx

@@ -13,12 +13,12 @@ Starting with version 2.1, Glide introduces a new synchronous Python client, alo
 
 The following features were added to the sync client in subsequent releases:
 
-| Feature                 | Version                                                                 |
-| ----------------------- | ----------------------------------------------------------------------- |
-| Cluster Scan            | [v2.2.0](https://github.com/valkey-io/valkey-glide/releases/tag/v2.2.0) |
-| In-flight Request Limit | [v2.3.0](https://github.com/valkey-io/valkey-glide/releases/tag/v2.3.0) |
-| OpenTelemetry           | [v2.3.0](https://github.com/valkey-io/valkey-glide/releases/tag/v2.3.0) |
-| PubSub                  | [v2.3.0](https://github.com/valkey-io/valkey-glide/releases/tag/v2.3.0) |
+| Feature                  | Version                                                                 |
+| ------------------------ | ----------------------------------------------------------------------- |
+| Cluster Scan             | [v2.2.0](https://github.com/valkey-io/valkey-glide/releases/tag/v2.2.0) |
+| In-flight Request Limit  | [v2.3.0](https://github.com/valkey-io/valkey-glide/releases/tag/v2.3.0) |
+| OpenTelemetry            | [v2.3.0](https://github.com/valkey-io/valkey-glide/releases/tag/v2.3.0) |
+| PubSub                   | [v2.3.0](https://github.com/valkey-io/valkey-glide/releases/tag/v2.3.0) |
 
 ## Installing
 
@@ -78,9 +78,9 @@ The following example compares the synchronous vs asynchronous clients usage for
     )
 
     addresses = [
-        NodeAddress(host="primary.example.com", port=6379),
-        NodeAddress(host="replica1.example.com", port=6379),
-        NodeAddress(host="replica2.example.com", port=6379)
+       NodeAddress(host="primary.example.com", port=6379),
+       NodeAddress(host="replica1.example.com", port=6379),
+       NodeAddress(host="replica2.example.com", port=6379)
       ]
     client_config = GlideClientConfiguration(addresses)
 
@@ -97,3 +97,107 @@ The following example compares the synchronous vs asynchronous clients usage for
     ```
   </TabItem>
 </Tabs>
+
+
+## Zero-Copy Buffers
+
+When reading large values (KV-cache blobs, embeddings, serialized tensors), the default `get` and `mget` commands allocate a new Python `bytes` object for each value returned. For high-throughput workloads this allocation overhead adds up. Zero-copy buffers let you pass pre-allocated memory so values are written directly into your buffers without intermediate allocations.
+
+:::caution[Sync Client Only]
+Zero-copy buffer parameters are available only on the synchronous client (`glide_sync`). The async client does not support this feature.
+:::
+
+### Single key: `get` with buffer
+
+Pass a writable `memoryview` to `get` to receive the value directly in your buffer:
+
+```python
+buf = bytearray(4096)
+view = memoryview(buf)
+
+result = client.get("my_key", buffer=view)
+if result is not None:
+    bytes_written = int(result)
+    value = bytes(buf[:bytes_written])
+```
+
+When a `buffer` is provided, `get` returns the number of bytes written as a byte string (e.g. `b'4096'`), or `None` if the key does not exist.
+
+### Multiple keys: `mget` with buffers
+
+The `buffers` parameter extends the same pattern to multi-key reads:
+
+```python
+keys = ["embedding:1", "embedding:2", "embedding:3"]
+BUFFER_SIZE = 8192
+
+# Pre-allocate one buffer per key
+buffers = [memoryview(bytearray(BUFFER_SIZE)) for _ in keys]
+
+results = client.mget(keys, buffers=buffers)
+
+for i, result in enumerate(results):
+    if result is None:
+        print(f"{keys[i]}: missing")
+    else:
+        bytes_written = int(result)
+        # Access the value directly from the buffer — no extra copy
+        value = bytes(buffers[i][:bytes_written])
+        print(f"{keys[i]}: {bytes_written} bytes")
+```
+
+:::tip[Buffer Sizing]
+Size buffers appropriately for your expected values. If a value exceeds its buffer capacity, a `RequestError` is raised. For variable-sized data, consider using a conservative upper bound or implementing retry logic with larger buffers.
+:::
+
+Each element in the returned list is either:
+- A byte string containing the number of bytes written (e.g. `b'8192'`) — read the value from `buffers[i][:int(result)]`
+- `None` — the key does not exist
+
+### Requirements
+
+- **Writable and C-contiguous**: Each buffer must be a writable, C-contiguous `memoryview`. The simplest way to create one is `memoryview(bytearray(size))`.
+- **Same length as keys**: The `buffers` list must have exactly the same number of elements as `keys`.
+
+### Error Handling
+
+- **Buffer too small**: If a value exceeds its buffer capacity, a `RequestError` with "exceeds buffer capacity" is raised.
+- **Length mismatch**: If the `buffers` list length differs from `keys`, a `ValueError` is raised.
+- **Invalid buffer type**: Non-writable or non-C-contiguous buffers raise a `TypeError`.
+
+```python
+try:
+    small_buf = memoryview(bytearray(10))  # Too small for large values
+    result = client.get("large_key", buffer=small_buf)
+except RequestError as e:
+    if "exceeds buffer capacity" in str(e):
+        # Retry with a larger buffer
+        larger_buf = memoryview(bytearray(8192))
+        result = client.get("large_key", buffer=larger_buf)
+```
+
+### Complete example
+
+```python
+from glide_sync import GlideClient, GlideClientConfiguration, NodeAddress
+
+config = GlideClientConfiguration([NodeAddress("localhost", 6379)])
+client = GlideClient.create(config)
+
+# Store some test data
+client.mset({"vec:1": b"A" * 4096, "vec:2": b"B" * 2048})
+
+# Read with zero-copy buffers
+keys = ["vec:1", "vec:2", "vec:missing"]
+bufs = [memoryview(bytearray(8192)) for _ in keys]
+
+results = client.mget(keys, buffers=bufs)
+# results == [b'4096', b'2048', None]
+
+for i, r in enumerate(results):
+    if r is None:
+        print(f"{keys[i]} does not exist")
+    else:
+        n = int(r)
+        print(f"{keys[i]}: {n} bytes -> {bytes(bufs[i][:n])[:20]}...")
+```