Fix several off-by-one issues in UploadFileMessage

We now fuzz UploadFileMessage, generating random files and checking they
round-trip correctly.

The joy of having a long-lasting refactor branch with an absolutely
massive diff, is that you end up spotting bugs, and then it's a massive
pain to merge the fix back into trunk!

gradle/libs.versions.toml

@@ -0,0 +1,29 @@
+[versions]
+autoService = "1.0.1"
+kotlin = "1.7.10"
+kotlin-coroutines = "1.6.0"
+
+# Testing
+hamcrest = "2.2"
+jqwik = "1.7.0"
+junit = "5.9.1"
+
+[libraries]
+autoService = { module = "com.google.auto.service:auto-service", version.ref = "autoService" }
+kotlin-coroutines = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-core", version.ref = "kotlin-coroutines" }
+kotlin-stdlib = { module = "org.jetbrains.kotlin:kotlin-stdlib-jdk8", version.ref = "kotlin" }
+
+# Testing
+hamcrest = { module = "org.hamcrest:hamcrest", version.ref = "hamcrest" }
+jqwik-api = { module = "net.jqwik:jqwik-api", version.ref = "jqwik" }
+jqwik-engine = { module = "net.jqwik:jqwik-engine", version.ref = "jqwik" }
+junit-jupiter-api = { module = "org.junit.jupiter:junit-jupiter-api", version.ref = "junit" }
+junit-jupiter-engine = { module = "org.junit.jupiter:junit-jupiter-engine", version.ref = "junit" }
+junit-jupiter-params = { module = "org.junit.jupiter:junit-jupiter-params", version.ref = "junit" }
+
+[bundles]
+kotlin = ["kotlin-stdlib", "kotlin-coroutines"]
+
+# Testing
+test = ["junit-jupiter-api", "junit-jupiter-params", "hamcrest", "jqwik-api"]
+testRuntime = ["junit-jupiter-engine", "jqwik-engine"]