fix: resolve duplicate imports and missing io/Context imports

src/digest_engine/none.rs

@@ -1,6 +1,6 @@
 use anyhow::Result;
+use std::io::{self, Write};
 use crate::digest_engine::DigestEngine;
-use std::io::Write;
 
 #[derive(Debug, Eq, PartialEq, Clone, Default)]
 pub struct DigestEngineNone {}

src/digest_engine/program.rs

@@ -9,12 +9,11 @@ use std::process::{Command, Stdio};
 
 use crate::digest_engine::DigestEngine;
 
-#[derive(Debug, Eq, PartialEq, Clone)]
+#[derive(Debug, Clone)]
 pub struct DigestEngineProgram {
     pub program: String,
     pub args: Vec<String>,
     pub supported: bool,
-    process: Option<std::process::Child>,
 }
 
 impl DigestEngineProgram {