> echo hello
-> data: hello

> info 
-> data: {"size":0}

> commit 
-> data: 0x

> append_tx abc
-> code: OK

> info 
-> data: {"size":1}

> commit 
-> data: 0x750502FC7E84BBD788ED589624F06CFA871845D1

> query abc
-> code: OK
-> data: {"index":0,"value":"abc","exists":true}

> append_tx def=xyz
-> code: OK

> commit 
-> data: 0x76393B8A182E450286B0694C629ECB51B286EFD5

> query def
-> code: OK
-> data: {"index":1,"value":"xyz","exists":true}