The buffered-io crate implements buffering for the embedded-io/embedded-io-async Read and Write traits.
rust
let uart_tx = ...;
let mut write_buf = [0; 120];
let buffering = BufferedWrite::new(uart_tx, &mut write_buf);
buffering.write(b"hello").await?; // This write is buffered
buffering.write(b" ").await?; // This write is also buffered
buffering.write(b"world").await?; // This write is also buffered
buffering.flush().await?; // The string "hello world" is written to uart in one write