# WritePackedFixedString64Delta(FixedString64Bytes, FixedString64Bytes, in StreamCompressionModel)

> Writes a delta FixedString64Bytes value to the data stream using a StreamCompressionModel.

## Definition

* **Type:** Method
* **Namespace:** [Unity.Collections](/engine/6000.7/script-reference/unity/collections.md)
* **Assembly:** UnityEngine.ManagedKernelModule

## WritePackedFixedString64Delta(FixedString64Bytes, FixedString64Bytes, StreamCompressionModel)

```csharp
public bool WritePackedFixedString64Delta(FixedString64Bytes str, FixedString64Bytes baseline, in StreamCompressionModel model)
```

### Parameters

**** (\[FixedString64Bytes]\(/engine/6000.7/script-reference/unity/collections/fixedstring64bytes)): The current `FixedString64Bytes` value.**** (\[FixedString64Bytes]\(/engine/6000.7/script-reference/unity/collections/fixedstring64bytes)): The previous `FixedString64Bytes` value, used to compute the diff.**** (\[StreamCompressionModel]\(/engine/6000.7/script-reference/unity/collections/streamcompressionmodel)): [StreamCompressionModel](/engine/6000.7/script-reference/unity/collections/streamcompressionmodel.md) model for writing value in a packed manner.

### Returns

| Type                                                          | Description                      |
| ------------------------------------------------------------- | -------------------------------- |
| [bool](https://learn.microsoft.com/dotnet/api/system.boolean) | Whether the write was successful |