Propose a str opcode with a 1-byte length

pep-3154.txt

@@ -72,6 +72,13 @@ could use a binary encoding instead.
 It seems that all other opcodes emitted when using protocol 3 already use
 binary encoding.
 
+Better string encoding
+----------------------
+
+Short str objects currently have their length coded as a 4-bytes integer,
+which is wasteful.  A specific opcode with a 1-byte length would make
+many pickles smaller.
+
 
 
 Acknowledgments