pt 1 in reviving the android build (copied from pm 28a1, wish me luck)

mobile/android/thirdparty/ch/boye/httpclientandroidlib/client/ConnectionBackoffStrategy.java

@@ -0,0 +1,64 @@
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+package ch.boye.httpclientandroidlib.client;
+
+import ch.boye.httpclientandroidlib.HttpResponse;
+
+/**
+ * When managing a dynamic number of connections for a given route, this
+ * strategy assesses whether a given request execution outcome should
+ * result in a backoff signal or not, based on either examining the
+ * <code>Throwable</code> that resulted or by examining the resulting
+ * response (e.g. for its status code).
+ *
+ * @since 4.2
+ *
+ */
+public interface ConnectionBackoffStrategy {
+
+    /**
+     * Determines whether seeing the given <code>Throwable</code> as
+     * a result of request execution should result in a backoff
+     * signal.
+     * @param t the <code>Throwable</code> that happened
+     * @return <code>true</code> if a backoff signal should be
+     *   given
+     */
+    boolean shouldBackoff(Throwable t);
+
+    /**
+     * Determines whether receiving the given {@link HttpResponse} as
+     * a result of request execution should result in a backoff
+     * signal. Implementations MUST restrict themselves to examining
+     * the response header and MUST NOT consume any of the response
+     * body, if any.
+     * @param resp the <code>HttpResponse</code> that was received
+     * @return <code>true</code> if a backoff signal should be
+     *   given
+     */
+    boolean shouldBackoff(HttpResponse resp);
+}