Blocking `read_write` test failure

[agerasev]

---- tests::write_read stdout ----
thread '<unnamed>' panicked at blocking/src/tests.rs:134:9:
assertion `left == right` failed
  left: 2300
 right: 2304
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
thread 'tests::write_read' panicked at blocking/src/tests.rs:139:27:
called `Result::unwrap()` on an `Err` value: Any { .. }