Remove simplelog crate and MaybeWriteLogger type

[ci skip-build-wheels]

src/rust/engine/logging/Cargo.toml

@@ -12,9 +12,7 @@ lazy_static = "1"
 log = "0.4"
 num_enum = "0.4"
 parking_lot = "0.11"
-simplelog = "0.7.4"
-# TODO: See #10291.
-tokio = { version = "=0.2.20", features = ["rt-util"] }
+tokio = { version = "=0.2.20", features = ["rt-util"] } # TODO: see https://github.com/pantsbuild/pants/issues/10291
 uuid = { version = "0.7", features = ["v4"] }
 
 [build-dependencies]

src/rust/engine/logging/src/logger.rs

@@ -16,7 +16,6 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use lazy_static::lazy_static;
 use log::{debug, log, max_level, set_logger, set_max_level, LevelFilter, Log, Metadata, Record};
 use parking_lot::Mutex;
-use simplelog::WriteLogger;
 use tokio::task_local;
 use uuid::Uuid;
 
@@ -201,32 +200,6 @@ impl Log for PantsLogger {
   fn flush(&self) {}
 }
 
-struct MaybeWriteLogger<W: Write + Send + 'static> {
-  inner: Option<Box<WriteLogger<W>>>,
-}
-
-impl<W: Write + Send + 'static> Log for MaybeWriteLogger<W> {
-  fn enabled(&self, _metadata: &Metadata) -> bool {
-    // PantsLogger will have already filtered using the global filter.
-    true
-  }
-
-  fn log(&self, record: &Record) {
-    if !self.enabled(record.metadata()) {
-      return;
-    }
-    if let Some(ref logger) = self.inner {
-      logger.log(record);
-    }
-  }
-
-  fn flush(&self) {
-    if let Some(ref logger) = self.inner {
-      logger.flush();
-    }
-  }
-}
-
 ///
 /// Thread- or task-local context for where the Logger should send log statements.
 ///