dotnet-file-io
dotnet-file-io
File I/O patterns for .NET applications. Covers FileStream construction with async flags, RandomAccess API for thread-safe offset-based I/O, File convenience methods, FileSystemWatcher event handling and debouncing, MemoryMappedFile for large files and IPC, path handling security (Combine vs Join), secure temp file creation, cross-platform considerations, IOException hierarchy, and buffer sizing guidance.
Out of scope: PipeReader/PipeWriter and network I/O -- see [skill:dotnet-io-pipelines]. Async/await fundamentals -- see [skill:dotnet-csharp-async-patterns]. Span/Memory/ArrayPool deep patterns -- see [skill:dotnet-performance-patterns]. JSON and Protobuf serialization -- see [skill:dotnet-serialization]. BackgroundService lifecycle -- see [skill:dotnet-background-services]. Channel producer/consumer -- see [skill:dotnet-channels]. GC implications of pinned/memory-mapped backing arrays -- see [skill:dotnet-gc-memory]. File upload validation (IFormFile) -- see [skill:dotnet-input-validation].
For testable file system access, consider System.IO.Abstractions -- see [skill:dotnet-testing-strategy] for test isolation patterns.
Cross-references: [skill:dotnet-io-pipelines] for PipeReader/PipeWriter network I/O, [skill:dotnet-gc-memory] for POH and memory-mapped backing array GC implications, [skill:dotnet-performance-patterns] for Span/Memory basics and ArrayPool usage, [skill:dotnet-csharp-async-patterns] for async/await patterns used with file streams.
FileStream
Async Flag Requirement
FileStream async methods (ReadAsync, WriteAsync) silently block the calling thread unless the stream is opened with the async flag. This is the most common file I/O mistake in .NET code.
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