fetch address counters async

In this PR (https://github.com/poanetwork/blockscout/pull/2636)
we started fetching transactions and rewards in parallel using
elixir tasks.

This PR uses similar approach to fetch validation and transaction
counters on address page.

apps/block_scout_web/lib/block_scout_web/controllers/address_contract_controller.ex

@@ -1,7 +1,7 @@
 defmodule BlockScoutWeb.AddressContractController do
   use BlockScoutWeb, :controller
 
-  import BlockScoutWeb.AddressController, only: [transaction_count: 1, validation_count: 1]
+  import BlockScoutWeb.AddressController, only: [transaction_and_validation_count: 1]
 
   alias Explorer.{Chain, Market}
   alias Explorer.ExchangeRates.Token
@@ -20,14 +20,16 @@ defmodule BlockScoutWeb.AddressContractController do
 
     with {:ok, address_hash} <- Chain.string_to_address_hash(address_hash_string),
          {:ok, address} <- Chain.find_contract_address(address_hash, address_options, true) do
+      {transaction_count, validation_count} = transaction_and_validation_count(address_hash)
+
       render(
         conn,
         "index.html",
         address: address,
         coin_balance_status: CoinBalanceOnDemand.trigger_fetch(address),
         exchange_rate: Market.get_exchange_rate(Explorer.coin()) || Token.null(),
-        transaction_count: transaction_count(address_hash),
-        validation_count: validation_count(address_hash)
+        transaction_count: transaction_count,
+        validation_count: validation_count
       )
     else
       :error ->

apps/block_scout_web/lib/block_scout_web/controllers/address_controller.ex

@@ -69,6 +69,34 @@ defmodule BlockScoutWeb.AddressController do
     redirect(conn, to: address_transaction_path(conn, :index, id))
   end
 
+  def transaction_and_validation_count(%Hash{byte_count: unquote(Hash.Address.byte_count())} = address_hash) do
+    transaction_count_task =
+      Task.async(fn ->
+        transaction_count(address_hash)
+      end)
+
+    validation_count_task =
+      Task.async(fn ->
+        validation_count(address_hash)
+      end)
+
+    [transaction_count_task, validation_count_task]
+    |> Task.yield_many(:timer.seconds(30))
+    |> Enum.map(fn {_task, res} ->
+      case res do
+        {:ok, result} ->
+          result
+
+        {:exit, reason} ->
+          raise "Query fetching address counters terminated: #{inspect(reason)}"
+
+        nil ->
+          raise "Query fetching address counters timed out."
+      end
+    end)
+    |> List.to_tuple()
+  end
+
   def transaction_count(%Hash{byte_count: unquote(Hash.Address.byte_count())} = address_hash) do
     Chain.total_transactions_sent_by_address(address_hash)
   end

apps/block_scout_web/lib/block_scout_web/controllers/address_read_contract_controller.ex

@@ -12,7 +12,7 @@ defmodule BlockScoutWeb.AddressReadContractController do
   alias Explorer.ExchangeRates.Token
   alias Indexer.Fetcher.CoinBalanceOnDemand
 
-  import BlockScoutWeb.AddressController, only: [transaction_count: 1, validation_count: 1]
+  import BlockScoutWeb.AddressController, only: [transaction_and_validation_count: 1]
 
   def index(conn, %{"address_id" => address_hash_string}) do
     address_options = [
@@ -27,14 +27,16 @@ defmodule BlockScoutWeb.AddressReadContractController do
 
     with {:ok, address_hash} <- Chain.string_to_address_hash(address_hash_string),
          {:ok, address} <- Chain.find_contract_address(address_hash, address_options, true) do
+      {transaction_count, validation_count} = transaction_and_validation_count(address_hash)
+
       render(
         conn,
         "index.html",
         address: address,
         coin_balance_status: CoinBalanceOnDemand.trigger_fetch(address),
         exchange_rate: Market.get_exchange_rate(Explorer.coin()) || Token.null(),
-        transaction_count: transaction_count(address_hash),
-        validation_count: validation_count(address_hash)
+        transaction_count: transaction_count,
+        validation_count: validation_count
       )
     else
       :error ->

apps/block_scout_web/lib/block_scout_web/controllers/address_transaction_controller.ex

@@ -5,7 +5,7 @@ defmodule BlockScoutWeb.AddressTransactionController do
 
   use BlockScoutWeb, :controller
 
-  import BlockScoutWeb.AddressController, only: [transaction_count: 1, validation_count: 1]
+  import BlockScoutWeb.AddressController, only: [transaction_and_validation_count: 1]
   import BlockScoutWeb.Chain, only: [current_filter: 1, paging_options: 1, next_page_params: 3, split_list_by_page: 1]
 
   alias BlockScoutWeb.TransactionView
@@ -96,6 +96,8 @@ defmodule BlockScoutWeb.AddressTransactionController do
   def index(conn, %{"address_id" => address_hash_string} = params) do
     with {:ok, address_hash} <- Chain.string_to_address_hash(address_hash_string),
          {:ok, address} <- Chain.hash_to_address(address_hash) do
+      {transaction_count, validation_count} = transaction_and_validation_count(address_hash)
+
       render(
         conn,
         "index.html",
@@ -103,8 +105,8 @@ defmodule BlockScoutWeb.AddressTransactionController do
         coin_balance_status: CoinBalanceOnDemand.trigger_fetch(address),
         exchange_rate: Market.get_exchange_rate(Explorer.coin()) || Token.null(),
         filter: params["filter"],
-        transaction_count: transaction_count(address_hash),
-        validation_count: validation_count(address_hash),
+        transaction_count: transaction_count,
+        validation_count: validation_count,
         current_path: current_path(conn)
       )
     else