# IEvictionStrategy Methods

[Type overview](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.providers.streams.common.ievictionstrategy/)

## OnBlockAllocated(FixedSizeBuffer) {#onblockallocated-orleans-providers-streams-common-fixedsizebuffer-dd1fc9b7}

[Dedicated page](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.providers.streams.common.ievictionstrategy/methods/onblockallocated-orleans-providers-streams-common-fixedsizebuffer-dd1fc9b7/)

```csharp
public abstract void OnBlockAllocated(FixedSizeBuffer newBlock)
```

Method which should be called when data adapter allocated a new block

### Parameters

- `newBlock` (`FixedSizeBuffer`): The new block.

## PerformPurge(DateTime) {#performpurge-system-datetime-f28007b5}

[Dedicated page](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.providers.streams.common.ievictionstrategy/methods/performpurge-system-datetime-f28007b5/)

```csharp
public abstract void PerformPurge(DateTime utcNow)
```

Method which should be called when pulling agent try to do a purge on the cache

### Parameters

- `utcNow` (`DateTime`): The current time (UTC)