perf: buffer writes when serializing json

ethers-solc/src/cache.rs

@@ -16,6 +16,7 @@ use std::{
         hash_map, BTreeSet, HashMap, HashSet,
     },
     fs::{self},
+    io::Write,
     path::{Path, PathBuf},
     time::{Duration, UNIX_EPOCH},
 };
@@ -139,7 +140,9 @@ impl SolFilesCache {
             self.len(),
             path.display()
         );
-        serde_json::to_writer_pretty(file, self)?;
+        let mut writer = std::io::BufWriter::with_capacity(1024 * 256, file);
+        serde_json::to_writer_pretty(&mut writer, self)?;
+        writer.flush().map_err(|e| SolcError::io(e, path))?;
         tracing::trace!("cache file located: \"{}\"", path.display());
         Ok(())
     }

ethers-solc/src/compile/mod.rs

@@ -8,7 +8,7 @@ use semver::{Version, VersionReq};
 use serde::{de::DeserializeOwned, Deserialize, Serialize};
 use std::{
     fmt,
-    io::BufRead,
+    io::{BufRead, Write},
     path::{Path, PathBuf},
     process::{Command, Output, Stdio},
     str::FromStr,
@@ -572,7 +572,9 @@ impl Solc {
             .spawn()
             .map_err(|err| SolcError::io(err, &self.solc))?;
         let stdin = child.stdin.take().expect("Stdin exists.");
-        serde_json::to_writer(stdin, input)?;
+        let mut writer = std::io::BufWriter::new(stdin);
+        serde_json::to_writer(&mut writer, input)?;
+        writer.flush().map_err(|e| SolcError::io(e, &self.solc))?;
         compile_output(child.wait_with_output().map_err(|err| SolcError::io(err, &self.solc))?)
     }