Add Headers#to_a method

- Adds Headers#to_a method that returns the fields array
- Provides compatibility with standard Ruby array conversion pattern
- Includes comprehensive tests for the new method

Author: samuel-williams-shopify

lib/protocol/http/headers.rb

@@ -108,6 +108,11 @@ def flatten
 			# @attribute [Array] An array of `[key, value]` pairs.
 			attr :fields
 
+			# @returns [Array] The fields of the headers.
+			def to_a
+				@fields
+			end
+			
 			# @returns [Boolean] Whether there are any trailers.
 			def trailer?
 				@tail != nil

test/protocol/http/headers.rb

@@ -148,6 +148,20 @@
 		end
 	end
 
+	with "#to_a" do
+		it "should return the fields array" do
+			expect(headers.to_a).to be == fields
+		end
+		
+		it "should return the same object as fields" do
+			expect(headers.to_a).to be_equal(headers.fields)
+		end
+		
+		it "should return an array" do
+			expect(headers.to_a).to be_a(Array)
+		end
+	end
+	
 	with "#to_h" do
 		it "should generate array values for duplicate keys" do
 			expect(headers.to_h["set-cookie"]).to be == ["hello=world", "foo=bar"]