perf: allow keep alive for HEAD requests

lib/client.js

@@ -769,7 +769,7 @@ class Parser {
     }
 
     if (request.method === 'HEAD') {
-      assert(socket[kReset])
+      assert(request.reset === false || socket[kReset])
       return 1
     }
 
@@ -1376,8 +1376,8 @@ function write (client, request) {
     socket[kReset] = true
   }
 
-  if (reset) {
-    socket[kReset] = true
+  if (reset != null) {
+    socket[kReset] = reset
   }
 
   if (client[kMaxRequests] && socket[kCounter]++ >= client[kMaxRequests]) {

test/client-head-reset-override.js

@@ -0,0 +1,42 @@
+'use strict'
+
+const { createServer } = require('http')
+const { test } = require('tap')
+const { Client } = require('..')
+
+test('override HEAD reset', (t) => {
+  const server = createServer((req, res) => {
+    res.setHeader('connection', 'keep-alive')
+    res.end()
+  })
+  t.teardown(server.close.bind(server))
+
+  server.listen(0, () => {
+    const client = new Client(`http://localhost:${server.address().port}`)
+    t.teardown(client.close.bind(client))
+
+    client.on('disconnect', () => {
+      t.fail()
+    })
+
+    client.request({
+      path: '/',
+      method: 'HEAD',
+      reset: false
+    }, (err, res) => {
+      t.error(err)
+      res.body.resume()
+    })
+
+    client.request({
+      path: '/',
+      method: 'HEAD',
+      reset: false
+    }, (err, res) => {
+      t.error(err)
+      res.body.resume()
+      console.error("ASD")
+      t.end()
+    })
+  })
+})