StreamReader is not zero-copy

[Luv-Ray]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

There is a Vec<u8> in IPC Streaming Format, and I want to convert it to record batches.

For now my code is like this:

use bytes::Buf;

fn deserialize_stream_buf(buf: Vec<u8>) -> Vec<RecordBatch> {
    let buf = buf.reader();
    let reader = StreamReader::try_new(buf, None).unwrap();
    reader.map(|b| b.unwrap()).collect()
}

But it's not zero-copy, each time next() is called, StreamReader will copy the data.

Describe the solution you'd like

read a memory region in IPC Streaming Format with zero-copy.

Describe alternatives you've considered

Is there could be an API like FileReader? Take ownership of the memery region rather than borrowing it.

[tustvold]

I believe #5531 is what you're after (not yet released)

[Luv-Ray]

Thanks, I will wait for the release :)