Don't write to context in case of an exception

src/kemal/common_exception_handler.cr

@@ -10,8 +10,6 @@ module Kemal
       rescue Kemal::Exceptions::CustomException
         status_code = context.response.status_code
         if Kemal.config.error_handlers.has_key?(status_code)
-          context.response.reset
-          context.response.content_type = "text/html"
           context.response.print Kemal.config.error_handlers[status_code].call(context)
           return context
         end

src/kemal/config.cr

@@ -7,7 +7,7 @@ module Kemal
     @server : HTTP::Server?
 
     property host_binding, ssl, port, env, public_folder, logging,
-      always_rescue, serve_static, server, error_handler
+      always_rescue, serve_static, server
 
     def initialize
       @host_binding = "0.0.0.0"

src/kemal/route_handler.cr

@@ -31,12 +31,13 @@ class Kemal::RouteHandler < HTTP::Handler
 
   # Processes the route if it's a match. Otherwise renders 404.
   def process_request(context)
-    return raise Kemal::Exceptions::RouteNotFound.new(context) unless context.route_defined?
+    raise Kemal::Exceptions::RouteNotFound.new(context) unless context.route_defined?
     route = context.route_lookup.payload as Route
-    context.response.print(route.handler.call(context))
+    content = route.handler.call(context)
     if Kemal.config.error_handlers.has_key?(context.response.status_code)
-      return raise Kemal::Exceptions::CustomException.new(context)
+      raise Kemal::Exceptions::CustomException.new(context)
     end
+    context.response.print(content)
     context
   end