public Builder withBlockchain(final MutableBlockchain blockchain) {
      this.blockchain = blockchain;
      return this;
    }
Sets the {@link MutableBlockchain} for the {@link ProtocolContext}.

@param blockchain the blockchain to be used in the protocol context.
@return the builder instance for chaining.
ethereum/core/src/main/java/org/hyperledger/besu/ethereum/ProtocolContext.java