Add a convenience method to determine the network a message is from

lib/btc_wire_proto.rb

@@ -428,7 +428,7 @@ module BtcWireProto
     string :command, :length => 12
     uint32 :payload_len, :value => lambda { payload.num_bytes }
     uint32 :checksum, :onlyif => :has_checksum?
-    
+
     choice :payload, :selection => :payload_choice do
       version         "version"
       addr_pre31402   "addr_pre31402"
@@ -446,10 +446,17 @@ module BtcWireProto
       null_payload    "null"
     end
 
+    # @return[Symbol] representation of the command this message contains
     def cmd_sym
       c = command.strip
       c == "" ? nil : c.to_sym
     end
+
+    # @return[Symbol] representation of the network this message belongs to
+    def network_name
+      NETWORKS[magic]
+    end
+
     # version and verack messages don't have a checksum. The rest do.
     # @return[Boolean] does this message header have a checksum field or not?
     def has_checksum?