added qos counsumer with readme example usage

README.md

@@ -33,6 +33,35 @@ pub fn main() !void {
 }
 ```
 
+qos consumer with prefetch_count=1 and message no_ack=false:
+
+```zig
+const std = @import("std");
+const amqp = @import("amqp");
+
+var rx_memory: [4096]u8 = undefined;
+var tx_memory: [4096]u8 = undefined;
+
+pub fn main() !void {
+    var conn = amqp.init(rx_memory[0..], tx_memory[0..]);
+    const addr = try std.net.Address.parseIp4("127.0.0.1", 5672);
+    var i: usize = 0;
+    try conn.connect(addr);
+
+    var ch = try conn.channel();
+    _ = try ch.queueDeclare("qos_consumer", .{}, null);
+
+    var couchdb_consumer = try ch.qosConsume("qos_consumer", .{ .prefetch_count = 1 }, .{ .no_ack = false }, null);
+
+    while (true) : (i += 1) {
+        const message = try couchdb_consumer.next();
+        _ = message.header;
+        const body = message.body;
+        // ...do something with the message
+        try couchdb_consumer.ack(false);
+}
+```
+
 ## Status
 
 The project is alpha with only basic functionality working and almost certainly is not
@@ -53,10 +82,10 @@ require.
 - None...and the binaries are small (other than a server to speak to)
 
 ```
-➜  zig-amqp git:(master) ✗ zig build-exe src/example.zig -O ReleaseSafe --strip 
-➜  zig-amqp git:(master) ✗ ldd example                                        
+➜  zig-amqp git:(master) ✗ zig build-exe src/example.zig -O ReleaseSafe --strip
+➜  zig-amqp git:(master) ✗ ldd example
         not a dynamic executable
-➜  zig-amqp git:(master) ✗ ls -l example                                      
+➜  zig-amqp git:(master) ✗ ls -l example
 -rwxr-xr-x. 1 malcolm malcolm 44872 Dec 20 04:26 example
 ```
 

src/basic.zig

@@ -10,13 +10,19 @@ pub const Basic = struct {
             exclusive: bool = false,
             no_wait: bool = false,
         };
+        pub const Qos = struct {
+            prefetch_size: u32 = 0,
+            prefetch_count: u16 = 1,
+            global: bool = false,
+        };
     };
 
     pub const Consumer = struct {
         connector: Connector,
+        delivery: proto.Basic.Deliver,
 
         pub fn next(consumer: *Consumer) !Message {
-            _ = try proto.Basic.awaitDeliver(&consumer.connector);
+            consumer.delivery = try proto.Basic.awaitDeliver(&consumer.connector);
             const header = try consumer.connector.awaitHeader();
             const body = try consumer.connector.awaitBody();
 
@@ -26,6 +32,14 @@ pub const Basic = struct {
                 .body = body,
             };
         }
+
+        pub fn ack(consumer: *Consumer, multiple: bool) !void {
+            _ = try proto.Basic.ackAsync(
+                &consumer.connector,
+                consumer.delivery.delivery_tag,
+                multiple,
+            );
+        }
     };
 
     pub const Publish = struct {

src/channel.zig

@@ -63,6 +63,32 @@ pub const Channel = struct {
 
         return Basic.Consumer{
             .connector = channel.connector,
+            .delivery = undefined,
+        };
+    }
+
+    pub fn qosConsume(channel: *Channel, name: []const u8, qos_options: Basic.Consume.Qos, options: Basic.Consume.Options, args: ?*Table) !Basic.Consumer {
+        _ = try proto.Basic.qosSync(
+            &channel.connector,
+            qos_options.prefetch_size,
+            qos_options.prefetch_count,
+            qos_options.global,
+        );
+
+        _ = try proto.Basic.consumeSync(
+            &channel.connector,
+            name,
+            "",
+            options.no_local,
+            options.no_ack,
+            options.exclusive,
+            options.no_wait,
+            args,
+        );
+
+        return Basic.Consumer{
+            .connector = channel.connector,
+            .delivery = undefined,
         };
     }
 };