I have a dumb question about the use of std_move. In 
BlockIO InterpreterInsertQuery::execute(): ln 312

https://github.com/ClickHouse/ClickHouse/blob/8ede5c736a6744f8daa6301d63697b8d4864725d/src/Interpreters/InterpreterInsertQuery.cpp#L310-L313

can this code block just written as 

```cpp
out_wrapper->setProcessListElement(context.getProcessListElement());
out_streams.emplace_back(std::move(out_wrapper););
```
or any specific reason?
#include <Interpreters/InterpreterInsertQuery.h>
#include <Access/AccessFlags.h>
#include <DataStreams/AddingDefaultBlockOutputStream.h>
#include <DataStreams/CheckConstraintsBlockOutputStream.h>
#include <DataStreams/CountingBlockOutputStream.h>
#include <DataStreams/InputStreamFromASTInsertQuery.h>
#include <DataStreams/NullAndDoCopyBlockInputStream.h>
#include <DataStreams/PushingToViewsBlockOutputStream.h>
#include <DataStreams/SquashingBlockOutputStream.h>
#include <DataStreams/copyData.h>