[feat] Support consumer seek by timestamp and reader seek for C Api (#118)

Fixes #82 


### Motivation

#82 

### Modifications

* Support seek by timestamp for the consumer
* Support seek by messageid and timestamp for the reader

Author: RobertIndie

include/pulsar/c/consumer.h

@@ -241,11 +241,51 @@ PULSAR_PUBLIC pulsar_result resume_message_listener(pulsar_consumer_t *consumer)
  */
 PULSAR_PUBLIC void pulsar_consumer_redeliver_unacknowledged_messages(pulsar_consumer_t *consumer);
 
+/**
+ * Reset the subscription associated with this consumer to a specific message id.
+ *
+ * @param consumer The consumer
+ * @param messageId The message id can either be a specific message or represent the first or last messages in
+ * the topic.
+ * @param callback The callback for this async operation
+ * @param ctx The context for the callback
+ */
 PULSAR_PUBLIC void pulsar_consumer_seek_async(pulsar_consumer_t *consumer, pulsar_message_id_t *messageId,
                                               pulsar_result_callback callback, void *ctx);
 
+/**
+ * Reset the subscription asynchronously associated with this consumer to a specific message id.
+ *
+ * @param consumer The consumer
+ * @param messageId The message id can either be a specific message or represent the first or last messages in
+ * the topic.
+ * @return Operation result
+ */
 PULSAR_PUBLIC pulsar_result pulsar_consumer_seek(pulsar_consumer_t *consumer, pulsar_message_id_t *messageId);
 
+/**
+ * Reset the subscription associated with this consumer to a specific message publish time.
+ *
+ * @param consumer The consumer
+ * @param timestamp The message publish time where to reposition the subscription. The timestamp format should
+ * be Unix time in milliseconds.
+ * @param callback The callback for this async operation
+ * @param ctx The context for the callback
+ */
+PULSAR_PUBLIC void pulsar_consumer_seek_by_timestamp_async(pulsar_consumer_t *consumer, uint64_t timestamp,
+                                                           pulsar_result_callback callback, void *ctx);
+
+/**
+ * Reset the subscription asynchronously associated with this consumer to a specific message publish time.
+ *
+ * @param consumer The consumer
+ * @param timestamp The message publish time where to reposition the subscription. The timestamp format should
+ * be Unix time in milliseconds.
+ * @return Operation result
+ */
+PULSAR_PUBLIC pulsar_result pulsar_consumer_seek_by_timestamp(pulsar_consumer_t *consumer,
+                                                              uint64_t timestamp);
+
 PULSAR_PUBLIC int pulsar_consumer_is_connected(pulsar_consumer_t *consumer);
 
 PULSAR_PUBLIC pulsar_result pulsar_consumer_get_last_message_id(pulsar_consumer_t *consumer,

include/pulsar/c/reader.h

@@ -59,6 +59,50 @@ PULSAR_PUBLIC pulsar_result pulsar_reader_read_next(pulsar_reader_t *reader, pul
 PULSAR_PUBLIC pulsar_result pulsar_reader_read_next_with_timeout(pulsar_reader_t *reader,
                                                                  pulsar_message_t **msg, int timeoutMs);
 
+/**
+ * Reset the subscription associated with this reader to a specific message id.
+ *
+ * @param reader The reader
+ * @param messageId The message id can either be a specific message or represent the first or last messages in
+ * the topic.
+ * @param callback The callback for this async operation
+ * @param ctx The context for the callback
+ */
+PULSAR_PUBLIC void pulsar_reader_seek_async(pulsar_reader_t *reader, pulsar_message_id_t *messageId,
+                                            pulsar_result_callback callback, void *ctx);
+
+/**
+ * Reset the subscription asynchronously associated with this reader to a specific message id.
+ *
+ * @param reader The reader
+ * @param messageId The message id can either be a specific message or represent the first or last messages in
+ * the topic.
+ * @return Operation result
+ */
+PULSAR_PUBLIC pulsar_result pulsar_reader_seek(pulsar_reader_t *reader, pulsar_message_id_t *messageId);
+
+/**
+ * Reset the subscription associated with this reader to a specific message publish time.
+ *
+ * @param reader The reader
+ * @param timestamp The message publish time where to reposition the subscription. The timestamp format should
+ * be Unix time in milliseconds.
+ * @param callback The callback for this async operation
+ * @param ctx The context for the callback
+ */
+PULSAR_PUBLIC void pulsar_reader_seek_by_timestamp_async(pulsar_reader_t *reader, uint64_t timestamp,
+                                                         pulsar_result_callback callback, void *ctx);
+
+/**
+ * Reset the subscription asynchronously associated with this reader to a specific message publish time.
+ *
+ * @param reader The reader
+ * @param timestamp The message publish time where to reposition the subscription. The timestamp format should
+ * be Unix time in milliseconds.
+ * @return Operation result
+ */
+PULSAR_PUBLIC pulsar_result pulsar_reader_seek_by_timestamp(pulsar_reader_t *reader, uint64_t timestamp);
+
 PULSAR_PUBLIC pulsar_result pulsar_reader_close(pulsar_reader_t *reader);
 
 PULSAR_PUBLIC void pulsar_reader_close_async(pulsar_reader_t *reader, pulsar_result_callback callback,

lib/c/c_Consumer.cc

@@ -156,6 +156,16 @@ pulsar_result pulsar_consumer_seek(pulsar_consumer_t *consumer, pulsar_message_i
     return (pulsar_result)consumer->consumer.seek(messageId->messageId);
 }
 
+void pulsar_consumer_seek_by_timestamp_async(pulsar_consumer_t *consumer, uint64_t timestamp,
+                                             pulsar_result_callback callback, void *ctx) {
+    consumer->consumer.seekAsync(timestamp,
+                                 std::bind(handle_result_callback, std::placeholders::_1, callback, ctx));
+}
+
+pulsar_result pulsar_consumer_seek_by_timestamp(pulsar_consumer_t *consumer, uint64_t timestamp) {
+    return (pulsar_result)consumer->consumer.seek(timestamp);
+}
+
 int pulsar_consumer_is_connected(pulsar_consumer_t *consumer) { return consumer->consumer.isConnected(); }
 
 pulsar_result pulsar_consumer_get_last_message_id(pulsar_consumer_t *consumer,

lib/c/c_Reader.cc

@@ -45,6 +45,26 @@ pulsar_result pulsar_reader_read_next_with_timeout(pulsar_reader_t *reader, puls
     return (pulsar_result)res;
 }
 
+void pulsar_reader_seek_async(pulsar_reader_t *reader, pulsar_message_id_t *messageId,
+                              pulsar_result_callback callback, void *ctx) {
+    reader->reader.seekAsync(messageId->messageId,
+                             std::bind(handle_result_callback, std::placeholders::_1, callback, ctx));
+}
+
+pulsar_result pulsar_reader_seek(pulsar_reader_t *reader, pulsar_message_id_t *messageId) {
+    return (pulsar_result)reader->reader.seek(messageId->messageId);
+}
+
+void pulsar_reader_seek_by_timestamp_async(pulsar_reader_t *reader, uint64_t timestamp,
+                                           pulsar_result_callback callback, void *ctx) {
+    reader->reader.seekAsync(timestamp,
+                             std::bind(handle_result_callback, std::placeholders::_1, callback, ctx));
+}
+
+pulsar_result pulsar_reader_seek_by_timestamp(pulsar_reader_t *reader, uint64_t timestamp) {
+    return (pulsar_result)reader->reader.seek(timestamp);
+}
+
 pulsar_result pulsar_reader_close(pulsar_reader_t *reader) { return (pulsar_result)reader->reader.close(); }
 
 void pulsar_reader_close_async(pulsar_reader_t *reader, pulsar_result_callback callback, void *ctx) {