Fix incompatibility with New Relic (#351)

Co-authored-by: Seth Holladay <me@seth-holladay.com>

package.json

@@ -57,7 +57,7 @@
 		"@types/node-fetch": "^2.5.10",
 		"@types/pify": "^5.0.0",
 		"abort-controller": "^3.0.0",
-		"ava": "^3.15.0",
+		"ava": "^4.0.0-alpha.2",
 		"body-parser": "^1.19.0",
 		"busboy": "^0.3.1",
 		"del-cli": "^3.0.1",
@@ -87,16 +87,9 @@
 		}
 	},
 	"ava": {
-		"files": [
-			"test/*"
-		],
 		"require": [
 			"./test/_require.ts"
 		],
-		"nonSemVerExperiments": {
-			"configurableModuleFormat": true,
-			"nextGenConfig": true
-		},
 		"extensions": {
 			"ts": "module"
 		},

source/core/Ky.ts

@@ -105,7 +105,8 @@ export class Ky {
 				throw new RangeError(`The \`timeout\` option cannot be greater than ${maxSafeTimeout}`);
 			}
 
-			await delay(1);
+			// Delay the fetch so that body method shortcuts can set the Accept header
+			await Promise.resolve();
 			let response = await ky._fetch();
 
 			for (const hook of ky._options.hooks.afterResponse) {