kahwee / bunki / 18694033265

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github

feat: add zero-copy streaming functions to file-utils

Add two new advanced Bun file I/O functions:

1. createFileWriter(filePath, highWaterMark)
   - Creates buffered file writer for incremental writes
   - Uses Bun's native API with configurable buffer size (default 1MB)
   - Perfect for streaming large files or building content incrementally
   - Zero-copy to disk with backpressure handling

2. writeToStdout(filePath)
   - Writes file content to stdout using zero-copy mechanism
   - Similar to `cat file.txt` but implemented in TypeScript
   - No data loaded into application memory during transfer
   - Useful for CLI tools that need to output file contents

Updated copyFile() documentation to emphasize zero-copy behavior:
- Bun.write(target, BunFile) uses kernel-level copy
- No application memory involved in file transfer
- Performance comparable to native OS tools

Added 3 comprehensive tests for new functions:
- Incremental write buffering with flush/end
- Stdout streaming without error
- Error handling for non-existent files

Test count: 163 → 166 tests (571 → 574 assertions)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

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