Constant RPC_SIMULATION_UNIQUE_TX_IDENTIFIER 

const RPC_SIMULATION_UNIQUE_TX_IDENTIFIER: B256;

Available on crate feature reth only.

Non-zero transaction identifier used only for RPC simulations.

RPC requests are not final signed transactions, so gas filling and other request normalization can make a simulated signing payload differ from the eventual submitted transaction. Use a fixed sentinel instead of deriving a misleading future channel id from the simulated payload.