async fn export_diff_inner(
ctx: &Arc<RPCState>,
params: ForestChainExportDiffParams,
chain_export_guard: &ChainExportGuard,
) -> Result<ApiExportResult>async fn export_diff_inner(
ctx: &Arc<RPCState>,
params: ForestChainExportDiffParams,
chain_export_guard: &ChainExportGuard,
) -> Result<ApiExportResult>