Add a query to estimate the gas of a contract call

[RickyLB]

Description

Hedera's EVM equivalence enables developers to deploy and execute smart contracts using standard EVM-compatible tools. Additionally, the Hedera SDK allows the execution of smart contract transactions (state-changing and query-based) via protobuf messages submitted to Consensus Nodes.

However, unlike typical EVM flows where transactions are encoded with RLP and submitted to a JSON-RPC endpoint, Hedera’s SDK can introduce friction for developers transitioning from other ecosystems.

Problem

Today, the SDK does not support a way to determine the gas of a contract call.

EVM developers, accustomed to estimating gas requirements as part of their workflow, face challenges using the SDK. Specifically:

The ContractCall transaction type allows setting a gas limit but does not support gas estimation. This absence of gas estimation is a core gap, making the SDK less developer-friendly for those familiar with Ethereum-like environments.

Solution

1. Add a new query type
2. Add get_gas_cost Support to ContractCall