docs: fix Bun server environment variable names and improve clarity (#5334)

Co-authored-by: Claude <[email protected]>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

Author: 3 people

docs/start/framework/react/hosting.md

@@ -269,20 +269,22 @@ export default defineConfig({
 
 #### Production Server with Bun
 
-Alternatively, you can use a custom server implementation.
+Alternatively, you can use a custom server implementation that leverages Bun's native APIs.
 
-We've created an optimized production server that provides intelligent static asset loading with configurable memory management.
+We provide a reference implementation that demonstrates one approach to building a production-ready Bun server. This example uses Bun-native functions for optimal performance and includes features like intelligent asset preloading and memory management.
 
-**Features:**
+**This is a starting point - feel free to adapt it to your needs or simplify it for your use case.**
 
-- **Hybrid loading strategy**: Small files (<5MB by default) are preloaded into memory, large files are served on-demand
-- **Configurable file filtering**: Use include/exclude patterns to control which files are preloaded
-- **Production-ready caching headers**: Automatic optimization for static assets
-- **Memory-efficient**: Smart memory management prevents excessive RAM usage
+**What this example demonstrates:**
+
+- Serving static assets using Bun's native file handling
+- Hybrid loading strategy (preload small files, serve large files on-demand)
+- Optional features like ETag support and Gzip compression
+- Production-ready caching headers
 
 **Quick Setup:**
 
-1. Copy the [`server.ts`](https://github.com/tanstack/router/blob/main/examples/react/start-bun/server.ts) file from the example in this repository to your project root
+1. Copy the [`server.ts`](https://github.com/tanstack/router/blob/main/examples/react/start-bun/server.ts) file from the example repository to your project root (or use it as inspiration for your own implementation)
 
 2. Build your application:
 
@@ -296,36 +298,57 @@ We've created an optimized production server that provides intelligent static as
    bun run server.ts
    ```
 
-**Configuration:**
+**Configuration (Optional):**
 
-The server can be configured using environment variables:
+The reference server implementation includes several optional configuration options via environment variables. You can use these as-is, modify them, or remove features you don't need:
 
 ```sh
-# Basic usage
+# Basic usage - just works out of the box
 bun run server.ts
 
-# Custom port
-PORT=8080 bun run server.ts
+# Common configurations
+PORT=8080 bun run server.ts  # Custom port
+ASSET_PRELOAD_VERBOSE_LOGGING=true bun run server.ts  # See what's happening
+```
+
+**Available Environment Variables:**
+
+| Variable                         | Description                                        | Default                                                                       |
+| -------------------------------- | -------------------------------------------------- | ----------------------------------------------------------------------------- |
+| `PORT`                           | Server port                                        | `3000`                                                                        |
+| `ASSET_PRELOAD_MAX_SIZE`         | Maximum file size to preload into memory (bytes)   | `5242880` (5MB)                                                               |
+| `ASSET_PRELOAD_INCLUDE_PATTERNS` | Comma-separated glob patterns for files to include | All files                                                                     |
+| `ASSET_PRELOAD_EXCLUDE_PATTERNS` | Comma-separated glob patterns for files to exclude | None                                                                          |
+| `ASSET_PRELOAD_VERBOSE_LOGGING`  | Enable detailed logging                            | `false`                                                                       |
+| `ASSET_PRELOAD_ENABLE_ETAG`      | Enable ETag generation                             | `true`                                                                        |
+| `ASSET_PRELOAD_ENABLE_GZIP`      | Enable Gzip compression                            | `true`                                                                        |
+| `ASSET_PRELOAD_GZIP_MIN_SIZE`    | Minimum file size for Gzip (bytes)                 | `1024` (1KB)                                                                  |
+| `ASSET_PRELOAD_GZIP_MIME_TYPES`  | MIME types eligible for Gzip                       | `text/,application/javascript,application/json,application/xml,image/svg+xml` |
+
+<details>
+<summary>Advanced configuration examples</summary>
 
-# Optimize for minimal memory usage (1MB preload limit)
-STATIC_PRELOAD_MAX_BYTES=1048576 bun run server.ts
+```sh
+# Optimize for minimal memory usage
+ASSET_PRELOAD_MAX_SIZE=1048576 bun run server.ts
 
 # Preload only critical assets
-STATIC_PRELOAD_INCLUDE="*.js,*.css" \
-STATIC_PRELOAD_EXCLUDE="*.map,vendor-*" \
+ASSET_PRELOAD_INCLUDE_PATTERNS="*.js,*.css" \
+ASSET_PRELOAD_EXCLUDE_PATTERNS="*.map,vendor-*" \
 bun run server.ts
 
-# Debug mode with verbose logging
-STATIC_PRELOAD_VERBOSE=true bun run server.ts
-```
+# Disable optional features
+ASSET_PRELOAD_ENABLE_ETAG=false \
+ASSET_PRELOAD_ENABLE_GZIP=false \
+bun run server.ts
 
-**Environment Variables:**
+# Custom Gzip configuration
+ASSET_PRELOAD_GZIP_MIN_SIZE=2048 \
+ASSET_PRELOAD_GZIP_MIME_TYPES="text/,application/javascript,application/json" \
+bun run server.ts
+```
 
-- `PORT`: Server port (default: 3000)
-- `STATIC_PRELOAD_MAX_BYTES`: Maximum file size to preload in bytes (default: 5242880 = 5MB)
-- `STATIC_PRELOAD_INCLUDE`: Comma-separated glob patterns for files to include
-- `STATIC_PRELOAD_EXCLUDE`: Comma-separated glob patterns for files to exclude
-- `STATIC_PRELOAD_VERBOSE`: Enable detailed logging (set to "true")
+</details>
 
 **Example Output:**