Use lifo scheduling by default

This is the default in node v15.6 but will improve performance by reusing the most recently used sockets first, reducing the likelihood of keepalive timeouts and ECONNRESETs.

Author: pluma

CHANGELOG.md

@@ -14,6 +14,16 @@ This driver uses semantic versioning:
 - A change in the major version (e.g. 1.Y.Z -> 2.0.0) indicates _breaking_
   changes that require changes in your code to upgrade.
 
+## [Unreleased]
+
+### Changed
+
+- Changed the default for `agentOptions.scheduling` to `"lifo"`
+
+  This is already the default in Node v15.6 but can reduce latency caused by
+  sockets expiring, especially with larger connection pools and infrequent
+  requests.
+
 ## [7.2.0] - 2020-12-02
 
 ### Added
@@ -1126,6 +1136,7 @@ For a detailed list of changes between pre-release versions of v7 see the
 
   Graph methods now only return the relevant part of the response body.
 
+[unreleased]: https://github.com/arangodb/arangojs/compare/v7.2.0...HEAD
 [7.2.0]: https://github.com/arangodb/arangojs/compare/v7.1.1...v7.2.0
 [7.1.1]: https://github.com/arangodb/arangojs/compare/v7.1.0...v7.1.1
 [7.1.0]: https://github.com/arangodb/arangojs/compare/v7.0.2...v7.1.0

src/connection.ts

@@ -519,6 +519,7 @@ export class Connection {
           maxSockets: 3,
           keepAlive: true,
           keepAliveMsecs: 1000,
+          scheduling: "lifo",
           ...config.agentOptions,
         };
     this._maxTasks = this._agentOptions.maxSockets;