# ArcBufferWriter.WriteAt(int, ReadOnlySpan<byte>)

[Type overview](/orleans/docs/api/csharp/microsoft.orleans.serialization/orleans.serialization.buffers.arcbufferwriter/) | [Methods](/orleans/docs/api/csharp/microsoft.orleans.serialization/orleans.serialization.buffers.arcbufferwriter/methods/)

[Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Orleans.Serialization/Buffers/ArcBufferWriter.cs#L156-L199)

```csharp
public void WriteAt(int offset, ReadOnlySpan<byte> value)
```

Overwrites bytes which have already been written to this buffer without changing the writer position.

### Parameters

- `offset` (`int`): The offset into the unconsumed bytes at which to start writing.
- `value` (`ReadOnlySpan<byte>`): The bytes to write.