What

Close stellar/stellar-rpc#330

This PR implements an integration load test to generate ledgers with soroban transactions. The test can be configured using the following parameters:

• transactions-per-ledger number of transactions per ledger
• transfers-per-tx number of asset transfers for each transaction
• ledgers number of ledgers to generate

The test will output ledgers number of ledgers each containing transactions-per-ledger transactions. Each transaction will have transfers-per-tx asset transfers. Half the asset transfers will result in movement among accounts and the other half of the transfers will result in movement between accounts and contracts.

The test is implemented as follows:

1. We use clients/stellarcore: Support more parameters from the upgrades endpoint #5546 to setup a private stellar network with unlimited soroban TPS.
2. We use a bulk transfer soroban contract which will allow us to have a single invocation which transfers assets to multiple destination accounts / contracts
3. We submit many soroban transactions to core
4. We merge ledgers together until we until we have sufficient data to populate the ledger data which satisfies the configuration parameters.

The transactions are carefully designed to make the merging operation safe. In particular, we ensure that the source / fee account of each transaction is not used or modified more than once within the batch of ledgers which will be merged.

Why

Currently, the number of soroban transections per ledger is limited but in the future we plan to raise that limit. But before doing so, we would like to use this tool to generate ledgers with a high volume of soroban activity so we can test the limits of horizon and rpc ingestion.

#5482

Known limitations

[N/A]