Currently we could use json2wal to convert the *.json to wal.File.

I found the the length of buffer of readline in json2wal is defalut

And the length of a line in json will exceed the defaultSize(4096) and report the following erros　because the size of byte of BlockPart

panic: failed to unmarshal json: unexpected end of JSON input

goroutine 1 [running]:
main.main()
	/root/gelgo/src/github.com/tendermint/tendermint/scripts/json2wal/main.go:66 +0x73f

I will use NewReaderSize(rd io.Reader, 70000) to fix this bug.