android: Fix some crashes, callstacks, and warnings I'm seeing in the logs.

src/packetstream.h

@@ -23,6 +23,12 @@ typedef struct _tf_packetstream_t tf_packetstream_t;
 */
 typedef void(tf_packetstream_onreceive_t)(int packet_type, const char* begin, size_t length, void* user_data);
 
+/**
+** A function called when a packetstream reads EOF.
+** @param user_data User data.
+*/
+typedef void(tf_packetstream_on_close_t)(void* user_data);
+
 /**
 ** Create a packet stream.
 ** @return The packet stream.
@@ -58,6 +64,14 @@ void tf_packetstream_send(tf_packetstream_t* stream, int packet_type, const char
 */
 void tf_packetstream_set_on_receive(tf_packetstream_t* stream, tf_packetstream_onreceive_t* callback, void* user_data);
 
+/**
+** Register a callback for when a stream reads EOF.
+** @param stream The packet stream.
+** @param callback The callback.
+** @param user_data User data to pass to the callback.
+*/
+void tf_packetstream_set_on_close(tf_packetstream_t* stream, tf_packetstream_on_close_t* callback, void* user_data);
+
 /**
 ** Close a packet stream.
 ** @param stream The packet stream.