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  "title" : "FSVolume.ReadWriteOperations"
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# FSVolume.ReadWriteOperations

Methods implemented for read and write operations that deliver data to and from the extension.

```
protocol ReadWriteOperations : NSObjectProtocol
```

## Overview

Most volumes conform to either this protocol or [`FSVolumeKernelOffloadedIOOperations`](/documentation/FSKit/FSVolumeKernelOffloadedIOOperations).
You can conform to both if you need to provide kernel-offloaded I/O only for certain files.
In that case, files with the [`inhibitKernelOffloadedIO`](/documentation/FSKit/FSItem/Attribute/inhibitKernelOffloadedIO) attribute set use this protocol, and those without it use [`FSVolumeKernelOffloadedIOOperations`](/documentation/FSKit/FSVolumeKernelOffloadedIOOperations).
A volume that doesn’t conform to either protocol can’t support any I/O operation.

> Deprecated: Use ``doc://FSKit/documentation/FSKit/FSVolume/ReadWriteHandler`` instead.

## Topics

### Reading and writing

[`read(from:at:length:into:replyHandler:)`](/documentation/FSKit/FSVolume/ReadWriteOperations/read(from:at:length:into:replyHandler:))

Reads the contents of the given file item.

[`FSMutableFileDataBuffer`](/documentation/FSKit/FSMutableFileDataBuffer)

A wrapper object for a data buffer.

[`write(contents:to:at:replyHandler:)`](/documentation/FSKit/FSVolume/ReadWriteOperations/write(contents:to:at:replyHandler:))

Writes contents to the given file item.


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