remove unmatched collapse comment
change macro name
growth initial buffer size
[decode] support int32 packed
[decode] support packed bool
[decode] support packed double
[decode] check infinite loop when decoding packed values
[deocde] add sint64 packed support
[decode] add fixed32 packed support
[decode] add fixed64 packed support
[decode] add float packed support
[decode] add int64 packed support
[decode] add sfixed32 packed support
[decode] add sfixed64 packed support
[decode] add sint32 packed support
for now, add packed support