xFabLedger: Extensible Ledger Storage for Hyperledger Fabric[B] PROCEEDINGS OF 2021 IEEE 11TH INTERNATIONAL CONFERENCE ON ELECTRONICS INFORMATION AND EMERGENCY COMMUNICATION (ICEIEC 2021) 2021 Pi, Bingfeng Pan, Yeda Zhou, Ence Sun, Jun Miyamae, Takeshi Morinaga, Masanobu