# `async_async_io`
Currently, only for `tokio`.
## `impl_trait_in_assoc_type` (Optional)
- use nightly channel;
- enable the feature `"impl_trait_in_assoc_type"`;
- look into the tests in `src/read.rs` and `src/write.rs` to see how to implement the traits.
## Usage
### `AsyncAsyncRead`
Definition:
```rust
pub struct AsyncReadBytes {
reader: io::Cursor<Vec<u8>>,
}
impl AsyncAsyncRead for AsyncReadBytes {
async fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
let len = std::io::Read::read(&mut self.reader, buf)?;
print!("{}.", len);
Ok(len)
}
}
```
Conversion to `AsyncRead`:
```rust
let stream = AsyncReadBytes::new(b"hello world".to_vec());
let mut async_read = PollRead::new(stream);
let mut writer = [0; 5];
async_read.read_exact(&mut writer).await.unwrap();
assert_eq!(&writer, b"hello");
```
### `AsyncAsyncWrite`
Definition:
```rust
pub struct AsyncWriteBytes {
writer: Vec<u8>,
}
impl AsyncAsyncWrite for AsyncWriteBytes {
async fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
print!("{}.", buf.len());
std::io::Write::write(&mut self.writer, buf)
}
async fn flush(&mut self) -> io::Result<()> {
std::io::Write::flush(&mut self.writer)
}
async fn shutdown(&mut self) -> io::Result<()> {
Ok(())
}
}
```
Conversion to `AsyncWrite`:
```rust
let writer = AsyncWriteBytes::new();
let mut async_write = PollWrite::new(writer);
async_write.write_all(b"hello world").await.unwrap();
assert_eq!(async_write.into_inner().written(), b"hello world");
```