fs: improve fsPromises writeFile performance

Increase the write chunk size in fsPromises writeFile
to improve performance.

Author: Linkgoron

lib/internal/fs/promises.js

@@ -7,7 +7,7 @@ const kIoMaxLength = 2 ** 31 - 1;
 // Note: This is different from kReadFileBufferLength used for non-promisified
 // fs.readFile.
 const kReadFileMaxChunkSize = 2 ** 14;
-const kWriteFileMaxChunkSize = 2 ** 14;
+const kWriteFileMaxChunkSize = 512 * 1024;
 
 const {
   ArrayPrototypePush,

test/parallel/test-fs-promises-file-handle-writeFile.js

@@ -30,7 +30,7 @@ async function validateWriteFile() {
 async function doWriteAndCancel() {
   const filePathForHandle = path.resolve(tmpDir, 'dogs-running.txt');
   const fileHandle = await open(filePathForHandle, 'w+');
-  const buffer = Buffer.from('dogs running'.repeat(10000), 'utf8');
+  const buffer = Buffer.from('dogs running'.repeat(512*1024), 'utf8');
   const controller = new AbortController();
   const { signal } = controller;
   process.nextTick(() => controller.abort());