ae.net.http.common: Add HttpRequest/HttpResponse.dup

Just enumerate the fields, nothing fancy for now.

net/http/common.d

@@ -75,6 +75,16 @@ public:
 	{
 		return Clock.currTime() - creationTime;
 	}
+
+	/// For `dup`.
+	protected void copyTo(typeof(this) other)
+	{
+		other.protocol = protocol;
+		other.protocolVersion = protocolVersion;
+		other.headers = headers.dup;
+		other.data = data.dup;
+		other.creationTime = creationTime;
+	}
 }
 
 // TODO: Separate this from an URL type
@@ -99,6 +109,24 @@ public:
 		this.resource = url;
 	} ///
 
+	/// For `dup`.
+	protected void copyTo(typeof(this) other)
+	{
+		super.copyTo(other);
+		other.method = method;
+		other.proxy = proxy;
+		other._resource = _resource;
+		other._port = _port;
+	}
+	alias copyTo = typeof(super).copyTo;
+
+	final typeof(this) dup()
+	{
+		auto result = new typeof(this);
+		copyTo(result);
+		return result;
+	} ///
+
 	/// Resource part of URL (everything after the hostname)
 	@property string resource() const pure nothrow @nogc
 	{
@@ -663,6 +691,21 @@ public:
 			}
 		}
 	}
+
+	protected void copyTo(typeof(this) other)
+	{
+		other.status = status;
+		other.statusMessage = statusMessage;
+		other.compressionLevel = compressionLevel;
+	}
+	alias copyTo = typeof(super).copyTo;
+
+	final typeof(this) dup()
+	{
+		auto result = new typeof(this);
+		copyTo(result);
+		return result;
+	} ///
 }
 
 /// Sets headers to request clients to not cache a response.

net/http/responseex.d

@@ -311,16 +311,21 @@ public:
 		.cacheForever(headers);
 	}
 
-	/// Construct and return a copy of this `HttpResponseEx`.
-	HttpResponseEx dup()
+	/// For `dup`.
+	protected void copyTo(typeof(this) other)
 	{
-		auto c = new HttpResponseEx;
-		c.status = this.status;
-		c.statusMessage = this.statusMessage;
-		c.headers = this.headers.dup;
-		c.data = this.data.dup;
-		return c;
+		super.copyTo(other);
+		other.pageTokens = pageTokens.dup;
+		other.errorTokens = errorTokens.dup;
 	}
+	alias copyTo = typeof(super).copyTo;
+
+	final typeof(this) dup()
+	{
+		auto result = new typeof(this);
+		copyTo(result);
+		return result;
+	} ///
 
 	/**
 	   Request a username and password.