Maximum number of transaction digests LedgerGrpcReader will put in a single
BatchGetTransactions call, matching the ledger gRPC/KV-RPC service’s own hard cap.
Implemented by LedgerGrpcReader for each key type whose Loader::load needs to stay under
the ledger service’s batch-size limit — DataLoader’s own max_batch_size is only a dispatch
trigger, not a hard cap on how many keys reach a single Loader::load call. load_chunk
supplies the raw, single-chunk fetch and chunk_size supplies the limit; load_chunked’s
default body splits keys into chunks, dispatches load_chunk concurrently per chunk, and
merges the results.