failed to resolve futures_timer

[0x8f701]

error[E0433]: failed to resolve: use of undeclared type or module `futures_timer`
  --> /home/cheng/.cargo/registry/src/github.com-1ecc6299db9ec823/async-std-1.6.2/src/utils.rs:84:29
   |
84 |     pub(crate) struct Timer(futures_timer::Delay);
   |                             ^^^^^^^^^^^^^ use of undeclared type or module `futures_timer`

error[E0433]: failed to resolve: use of undeclared type or module `futures_timer`
  --> /home/cheng/.cargo/registry/src/github.com-1ecc6299db9ec823/async-std-1.6.2/src/utils.rs:88:19
   |
88 |             Timer(futures_timer::Delay::new(dur))
   |                   ^^^^^^^^^^^^^ use of undeclared type or module `futures_timer`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0433`.
error: could not compile `async-std`.

To learn more, run the command again with --verbose.

with async-std@1.6.2, while run cargo check on target wasm, it printed this error

[0x8f701]

#861

[dignifiedquire]

fixed on master