DataBuffer (Flink : Runtime 2.0-preview1 API)

All Known Implementing Classes:

HashBasedDataBuffer, SortBasedDataBuffer, SortBuffer, TieredStorageSortBuffer
```
public interface DataBuffer
```
Data of different subpartitions can be appended to a DataBuffer and after the DataBuffer is full or finished, the appended data can be copied from it in subpartition index order.
The lifecycle of a DataBuffer can be: new, write, [read, reset, write], finish, read, release. There can be multiple [read, reset, write] operations before finish.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`append(ByteBuffer source, int targetSubpartition, Buffer.DataType dataType)`	Appends data of the specified subpartition to this `DataBuffer` and returns true if this `DataBuffer` is full.
`void`	`finish()`	Finishes this `DataBuffer` which means no record can be appended anymore.
`BufferWithSubpartition`	`getNextBuffer(org.apache.flink.core.memory.MemorySegment transitBuffer)`	Copies data in this `DataBuffer` to the target `MemorySegment` in subpartition index order and returns `BufferWithSubpartition` which contains the copied data and the corresponding subpartition index.
`boolean`	`hasRemaining()`	Returns true if not all data appended to this `DataBuffer` is consumed.
`boolean`	`isFinished()`	Whether this `DataBuffer` is finished or not.
`boolean`	`isReleased()`	Whether this `DataBuffer` is released or not.
`long`	`numTotalBytes()`	Returns the total number of bytes written to this `DataBuffer`.
`long`	`numTotalRecords()`	Returns the total number of records written to this `DataBuffer`.
`void`	`release()`	Releases this `DataBuffer` which releases all resources.

- Method Detail
  - append
```
boolean append(ByteBuffer source,
               int targetSubpartition,
               Buffer.DataType dataType)
        throws IOException
```
    Appends data of the specified subpartition to this DataBuffer and returns true if this DataBuffer is full.
    
    Throws:
    
    IOException
  - getNextBuffer
```
BufferWithSubpartition getNextBuffer(@Nullable
                                     org.apache.flink.core.memory.MemorySegment transitBuffer)
```
    Copies data in this DataBuffer to the target MemorySegment in subpartition index order and returns BufferWithSubpartition which contains the copied data and the corresponding subpartition index.
  - numTotalRecords
```
long numTotalRecords()
```
    Returns the total number of records written to this DataBuffer.
  - numTotalBytes
```
long numTotalBytes()
```
    Returns the total number of bytes written to this DataBuffer.
  - hasRemaining
```
boolean hasRemaining()
```
    Returns true if not all data appended to this DataBuffer is consumed.
  - finish
```
void finish()
```
    Finishes this DataBuffer which means no record can be appended anymore.
  - isFinished
```
boolean isFinished()
```
    Whether this DataBuffer is finished or not.
  - release
```
void release()
```
    Releases this DataBuffer which releases all resources.
  - isReleased
```
boolean isReleased()
```
    Whether this DataBuffer is released or not.