Add support for constructing headers with tail marker.

Author: ioquatix

lib/protocol/http/headers.rb

@@ -64,13 +64,15 @@ def self.[] headers
 			# Initialize the headers with the specified fields.
 			#
 			# @parameter fields [Array] An array of `[key, value]` pairs.
-			# @parameter indexed [Hash] A hash table of normalized headers, if available.
-			def initialize(fields = [], indexed = nil)
+			# @parameter tail [Integer | Nil] The index of the trailer start in the @fields array.
+			def initialize(fields = [], tail = nil, indexed: nil)
 				@fields = fields
-				@indexed = indexed
 
-				# Marks where trailer start in the @fields array.
-				@tail = nil
+				# Marks where trailer start in the @fields array:
+				@tail = tail
+				
+				# The cached index of headers:
+				@indexed = nil
 			end
 
 			# Initialize a copy of the headers.
@@ -86,8 +88,8 @@ def initialize_dup(other)
 			# Clear all headers.
 			def clear
 				@fields.clear
-				@indexed = nil
 				@tail = nil
+				@indexed = nil
 			end
 
 			# Flatten trailer into the headers, in-place.

test/protocol/http/headers.rb

@@ -9,16 +9,26 @@
 describe Protocol::HTTP::Headers do
 	let(:fields) do
 		[
+			["connection", "Keep-Alive"],
 			["Content-Type", "text/html"],
 			["Set-Cookie", "hello=world"],
 			["Accept", "*/*"],
 			["set-cookie", "foo=bar"],
-			["connection", "Keep-Alive"]
 		]
 	end
 
 	let(:headers) {subject[fields]}
 
+	with ".new" do
+		it "can construct headers with trailers" do
+			headers = subject.new(fields, 4)
+			expect(headers).to be(:trailer?)
+			expect(headers.trailer.to_a).to be == [
+				["set-cookie", "foo=bar"],
+			]
+		end
+	end
+	
 	with ".[]" do
 		it "can be constructed from frozen array" do
 			self.fields.freeze