refactor all write_alls to ensure flushing (#5567)

crates/nu-utils/src/lib.rs

@@ -1,3 +1,5 @@
 pub mod utils;
 
-pub use utils::enable_vt_processing;
+pub use utils::{
+    enable_vt_processing, stdout_write_all_and_flush, stdout_write_all_as_binary_and_flush,
+};

crates/nu-utils/src/utils.rs

@@ -1,4 +1,4 @@
-use std::io::Result;
+use std::io::{Result, Write};
 
 pub fn enable_vt_processing() -> Result<()> {
     #[cfg(windows)]
@@ -23,3 +23,23 @@ pub fn enable_vt_processing() -> Result<()> {
     }
     Ok(())
 }
+
+pub fn stdout_write_all_and_flush(output: String) -> Result<()> {
+    let stdout = std::io::stdout();
+    let ret = match stdout.lock().write_all(output.as_bytes()) {
+        Ok(_) => Ok(stdout.lock().flush()?),
+        Err(err) => Err(err),
+    };
+
+    ret
+}
+
+pub fn stdout_write_all_as_binary_and_flush(output: &[u8]) -> Result<()> {
+    let stdout = std::io::stdout();
+    let ret = match stdout.lock().write_all(output) {
+        Ok(_) => Ok(stdout.lock().flush()?),
+        Err(err) => Err(err),
+    };
+
+    ret
+}