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# append(buffer:allocator:flags:)

Adds a sliced memory block to a block buffer using a custom allocator.

```
func append(buffer: Slice<UnsafeMutableRawBufferPointer>, allocator: CFAllocator? = kCFAllocatorDefault, flags: CMBlockBuffer.Flags = []) throws
```

## Parameters

`buffer`

A block of memory to hold buffered data.

`allocator`

An allocator for the memory block.

`flags`

Feature and control flags.

---

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