diff --git a/lib/knot/protocol.rb b/lib/knot/protocol.rb
index 784c81c..98bf7c6 100644
--- a/lib/knot/protocol.rb
+++ b/lib/knot/protocol.rb
@@ -159,19 +159,24 @@ class Knot::Protocol
 
 	def snd sock: nil, **data
 		rsock = sock || @sock
-		s = ''.b
-		sock = StringIO.new s
-		sock.write [1].pack( 'c')
+		#s = ''.b
+		#sock = StringIO.new s
+		#sock.write [1].pack( 'c')
 		data[:flags] ||= ''
-		Idx::Idx.each do |n|
-			v = data[n.to_sym]&.to_s&.b
-			sock.write [n.to_i, v.size, v].pack( 'c na*')  if v
-		end
-		sock.write [3].pack( 'c')
-		sock.flush
+		ds =
+			Idx::Idx.
+				select {|n| data[n.to_sym] }.
+				map {|n| v = data[n.to_sym].to_s.b; [n.to_i, v.size, v ] }
+		s = (ds.flatten+[3]).pack( ('c na*'*ds.length)+'c').b
+		#Idx::Idx.each do |n|
+		#	v = data[n.to_sym]&.to_s&.b
+		#	sock.write [n.to_i, v.size, v].pack( 'c na*')  if v
+		#end
+		#sock.write [3].pack( 'c')
+		#sock.flush
 		if 0 >= @logger.sev_threshold
 			@logger.debug "send data #{data.inspect}"
-			@logger.debug "send raw  #{data.inspect}"
+			@logger.debug "send raw  #{s.inspect}"
 		end
 		rsock.write s
 		rsock.flush
@@ -194,8 +199,8 @@ class Knot::Protocol
 
 		def read n
 			s = @sock.read n
-			@str.insert -1, s
-			s
+			@str.insert -1, s  unless s.nil?
+			s || ''
 		end
 	end