What is the format of the Clique PoA genesis extradata field to set up the sealers?
This is an example:
"extraData": "0x000000000000000000000000000000000000000000000000000000000000000009b0888de6f7a33791d41b7041c71deef6c92d7616f5cf972fa3a9d139d1777387f06b073d99b43864ef6834ac2e543fb8c747b02a55087be4f955ac6a3a944c6c69fb1c2efb7f0593c1a1c6f406c95cb8f46fa71b33acddb030df8ef86efa305090f0f30000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
In the middle, all the sealers are stuck. I know we need to add zeros to left and right, but how many?