Compilation error - cannot find function `drain_to` in this scope

[JoyceBabu]

The project fails to compile. There is a missing function drain_to.

error[E0425]: cannot find function `drain_to` in this scope
   --> src/server.rs:279:13
    |
279 |             drain_to(&mut buf, pos as usize);
    |             ^^^^^^^^ not found in this scope