Fix linting warnings (#256)

* Use = to separate a named parameter from its default value

* Avoid return types on setters

* Mark unused Future results with unawaited

* Add pedantic analysis_options.yaml
diff --git a/analysis_options.yaml b/analysis_options.yaml
new file mode 100644
index 0000000..108d105
--- /dev/null
+++ b/analysis_options.yaml
@@ -0,0 +1 @@
+include: package:pedantic/analysis_options.yaml
diff --git a/lib/src/base_response.dart b/lib/src/base_response.dart
index 494f1a8..46f72d5 100644
--- a/lib/src/base_response.dart
+++ b/lib/src/base_response.dart
@@ -39,9 +39,9 @@
   BaseResponse(this.statusCode,
       {this.contentLength,
       this.request,
-      this.headers: const {},
-      this.isRedirect: false,
-      this.persistentConnection: true,
+      this.headers = const {},
+      this.isRedirect = false,
+      this.persistentConnection = true,
       this.reasonPhrase}) {
     if (statusCode < 100) {
       throw new ArgumentError("Invalid status code $statusCode.");
diff --git a/lib/src/browser_client.dart b/lib/src/browser_client.dart
index 4f49ec7..08225c2 100644
--- a/lib/src/browser_client.dart
+++ b/lib/src/browser_client.dart
@@ -6,6 +6,8 @@
 import 'dart:html';
 import 'dart:typed_data';
 
+import 'package:pedantic/pedantic.dart' show unawaited;
+
 import 'base_client.dart';
 import 'base_request.dart';
 import 'byte_stream.dart';
@@ -49,7 +51,7 @@
     request.headers.forEach(xhr.setRequestHeader);
 
     var completer = new Completer<StreamedResponse>();
-    xhr.onLoad.first.then((_) {
+    unawaited(xhr.onLoad.first.then((_) {
       // TODO(nweiz): Set the response type to "arraybuffer" when issue 18542
       // is fixed.
       var blob = xhr.response == null ? new Blob([]) : xhr.response;
@@ -72,15 +74,15 @@
       });
 
       reader.readAsArrayBuffer(blob);
-    });
+    }));
 
-    xhr.onError.first.then((_) {
+    unawaited(xhr.onError.first.then((_) {
       // Unfortunately, the underlying XMLHttpRequest API doesn't expose any
       // specific information about the error itself.
       completer.completeError(
           new ClientException("XMLHttpRequest error.", request.url),
           StackTrace.current);
-    });
+    }));
 
     xhr.send(bytes);
 
diff --git a/lib/src/multipart_request.dart b/lib/src/multipart_request.dart
index 1268669..00f410f 100644
--- a/lib/src/multipart_request.dart
+++ b/lib/src/multipart_request.dart
@@ -79,7 +79,7 @@
     return length + "--".length + _BOUNDARY_LENGTH + "--\r\n".length;
   }
 
-  void set contentLength(int value) {
+  set contentLength(int value) {
     throw new UnsupportedError("Cannot set the contentLength property of "
         "multipart requests.");
   }
diff --git a/lib/src/response.dart b/lib/src/response.dart
index 3c0323d..cb43d80 100644
--- a/lib/src/response.dart
+++ b/lib/src/response.dart
@@ -29,9 +29,9 @@
   /// Creates a new HTTP response with a string body.
   Response(String body, int statusCode,
       {BaseRequest request,
-      Map<String, String> headers: const {},
-      bool isRedirect: false,
-      bool persistentConnection: true,
+      Map<String, String> headers = const {},
+      bool isRedirect = false,
+      bool persistentConnection = true,
       String reasonPhrase})
       : this.bytes(_encodingForHeaders(headers).encode(body), statusCode,
             request: request,
@@ -43,9 +43,9 @@
   /// Create a new HTTP response with a byte array body.
   Response.bytes(List<int> bodyBytes, int statusCode,
       {BaseRequest request,
-      Map<String, String> headers: const {},
-      bool isRedirect: false,
-      bool persistentConnection: true,
+      Map<String, String> headers = const {},
+      bool isRedirect = false,
+      bool persistentConnection = true,
       String reasonPhrase})
       : bodyBytes = toUint8List(bodyBytes),
         super(statusCode,
diff --git a/lib/src/streamed_response.dart b/lib/src/streamed_response.dart
index d4cf806..55f055a 100644
--- a/lib/src/streamed_response.dart
+++ b/lib/src/streamed_response.dart
@@ -21,9 +21,9 @@
   StreamedResponse(Stream<List<int>> stream, int statusCode,
       {int contentLength,
       BaseRequest request,
-      Map<String, String> headers: const {},
-      bool isRedirect: false,
-      bool persistentConnection: true,
+      Map<String, String> headers = const {},
+      bool isRedirect = false,
+      bool persistentConnection = true,
       String reasonPhrase})
       : this.stream = toByteStream(stream),
         super(statusCode,
diff --git a/pubspec.yaml b/pubspec.yaml
index 9ef1317..f764311 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -11,6 +11,7 @@
   async: ">=1.10.0 <3.0.0"
   http_parser: ">=0.0.1 <4.0.0"
   path: ">=0.9.0 <2.0.0"
+  pedantic: "^1.0.0"
 
 dev_dependencies:
   test: ^1.3.0