diff --git a/.travis.yml b/.travis.yml
index afea3a0..d312762 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,19 @@
 os:
   - osx
+  - linux
 language: generic
 sudo: required
 dist: trusty
-osx_image: xcode9
+osx_image: xcode10
+install:
+  - eval "$(curl -sL https://swiftenv.fuller.li/install.sh)"
+env:
+  - SWIFT_VERSION=4.2
 script:
-  - swift build
+  - swift package update
   - swift test
+after_success: 
+  - git clone https://github.com/dn-m/Documentarian && cd Documentarian
+  - swift build -c release -Xswiftc -static-stdlib
+  - cd ../
+  - Documentarian/.build/Release/Documentarian
diff --git a/Package.resolved b/Package.resolved
index 22a2e19..db2c454 100644
--- a/Package.resolved
+++ b/Package.resolved
@@ -6,16 +6,25 @@
         "repositoryURL": "https://github.com/dn-m/Math",
         "state": {
           "branch": "master",
-          "revision": "d1284e043377c0b924cba2ffa2ab0b9aa9dd246f",
+          "revision": "075ebb5a934251ed7acbe4feace925ed7e322d0f",
           "version": null
         }
       },
+      {
+        "package": "PerformanceTesting",
+        "repositoryURL": "https://github.com/dn-m/PerformanceTesting",
+        "state": {
+          "branch": null,
+          "revision": "d48417c837b1a029dd9567dfa7b5ee3cfa9a0ec7",
+          "version": "0.3.0"
+        }
+      },
       {
         "package": "Structure",
         "repositoryURL": "https://github.com/dn-m/Structure",
         "state": {
           "branch": "master",
-          "revision": "81d894ed931864734c73f9507e5d2f147b40a363",
+          "revision": "11e920b1b883fe169c5ebb58e6489c0f28e9ad90",
           "version": null
         }
       }
diff --git a/Package.swift b/Package.swift
index 4aac7b4..7dcafc2 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:4.0
+// swift-tools-version:4.2
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
diff --git a/Sources/Timeline/Action.swift b/Sources/Timeline/Action.swift
index c3f8ff5..8ce77eb 100644
--- a/Sources/Timeline/Action.swift
+++ b/Sources/Timeline/Action.swift
@@ -5,7 +5,6 @@
 //  Created by James Bean on 8/3/17.
 //
 
-import Structure
 import DataStructures
 import Time
 
@@ -51,6 +50,6 @@ public class Action {
     }
 
     func hasAnyIdentifiers <S> (_ identifiers: S) -> Bool where S: Sequence, S.Element == String {
-        return identifiers.any(satisfy: hasIdentifier)
+        return self.identifiers.contains(where: identifiers.contains)
     }
 }
diff --git a/Sources/Timeline/Schedule.swift b/Sources/Timeline/Schedule.swift
index 2c7387f..2025125 100644
--- a/Sources/Timeline/Schedule.swift
+++ b/Sources/Timeline/Schedule.swift
@@ -7,7 +7,6 @@
 //
 
 import Foundation
-import StructureWrapping
 import DataStructures
 import Time
 
diff --git a/Sources/Timeline/SubSchedule.swift b/Sources/Timeline/SubSchedule.swift
index 19d160f..c0428fa 100644
--- a/Sources/Timeline/SubSchedule.swift
+++ b/Sources/Timeline/SubSchedule.swift
@@ -30,7 +30,7 @@ internal class SubSchedule {
         private func bump(_ actions: [Action], from offset: Seconds) {
             (actions as! [Action.Looping])
                 .map { action in (offset + action.interval, action) }
-                .forEach { offset, action in base.safelyAppend(action, toArrayWith: offset) }
+                .forEach { insert($1, at: $0) }
             base[offset] = nil
         }
     }
@@ -60,7 +60,7 @@ internal class SubSchedule {
 
     /// Add the given `action` at the given `offset`.
     internal func insert(_ action: Action, at offset: Seconds) {
-        base.safelyAppend(action, toArrayWith: offset)
+        base.safelyAppend(action, forKey: offset)
     }
 
     /// Insert the contents of the given `schedule` into this one.