public RespondingEthPeer build() {
      checkNotNull(ethProtocolManager, "Must configure EthProtocolManager");

      return RespondingEthPeer.create(
          ethProtocolManager,
          snapProtocolManager,
          chainHeadHash,
          totalDifficulty,
          estimatedHeight,
          peerValidators,
          isServingSnap,
          addToEthPeers);
    }
Create a responder that only responds with a fixed portion of the available data.

@param portion The portion of the available data to return, from 0 to 1
ethereum/eth/src/test/java/org/hyperledger/besu/ethereum/eth/manager/RespondingEthPeer.java