Initial sketch of bdp estimator
diff --git a/src/core/lib/transport/bdp_estimator.h b/src/core/lib/transport/bdp_estimator.h
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+++ b/src/core/lib/transport/bdp_estimator.h
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+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_TRANSPORT_BDP_ESTIMATOR_H
+#define GRPC_CORE_LIB_TRANSPORT_BDP_ESTIMATOR_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#define GRPC_BDP_SAMPLES 16
+#define GRPC_BDP_MIN_SAMPLES_FOR_ESTIMATE 3
+
+typedef struct grpc_bdp_estimator {
+ int64_t samples[GRPC_BDP_SAMPLES];
+ uint8_t num_samples;
+ uint8_t first_sample_idx;
+ bool sampling;
+} grpc_bdp_estimator;
+
+void grpc_bdp_estimator_init(grpc_bdp_estimator *estimator);
+void grpc_bdp_estimator_destroy(grpc_bdp_estimator *estimator);
+
+// Returns true if a reasonable estimate could be obtained
+bool grpc_bdp_estimator_get_estimate(grpc_bdp_estimator *estimator,
+ int64_t *estimate);
+// Returns true if the user should start a ping
+bool grpc_bdp_estimator_add_incoming_bytes(grpc_bdp_estimator *estimator,
+ int64_t num_bytes);
+// Completes a previously started ping
+void grpc_bdp_estimator_complete_ping(grpc_bdp_estimator *estimator);
+
+#endif