towards this value.
2. Block base fee change from fixed to floating.
Before upgrade, the block base fee is always 1Gwei.
After the upgrade, the base fee is depends on the gas usage of parent block, if the gas usage above the half of the block gas limit(ideally 15M),
朝着这个值。
2. 阻止基础费用从固定变为浮动。
升级前，区块基础费用始终为 1Gwei。
升级后，基础费用取决于父区块的gas使用量，如果gas使用量超过区块gas限制的一半（理想情况下为15M），