Merge branch 'debug-datastream' into 'main'

#[cfg(feature = "tokio")]

use tokio_util::compat::{FuturesAsyncReadCompatExt, FuturesAsyncWriteCompatExt};

use std::fmt;

use std::fmt::{self, Debug};

use std::io::Result as IoResult;

use std::pin::Pin;

    Flushing(Pin<Box<dyn Future<Output = (DataWriterImpl, Result<()>)> + Send>>),

}

impl fmt::Debug for DataWriterState {

impl Debug for DataWriterState {

    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {

        match self {

            DataWriterState::Closed => write!(f, "DataWriterState::Closed"),

}

/// Internal: the write part of a DataStream

#[derive(Debug)]

struct DataWriterImpl {

    /// The underlying StreamTarget object.

    s: StreamTarget,

    n_pending: usize,

}

impl Debug for DataWriterImpl {

    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {

        f.debug_struct("DataWriterImpl")

            .field("sr", &self.s)

            .field("n_pending", &self.n_pending)

            .finish_non_exhaustive()

    }

}

impl DataWriter {

    /// Helper for poll_flush() and poll_close(): Performs a flush, then

    /// closes the stream if should_close is true.

}

/// Wrapper for the read part of a DataStream

#[derive(Debug)]

struct DataReaderImpl {

    /// The underlying StreamReader object.

    s: StreamReader,