send frame when it exceeds 16K

libi2pd/NTCP2.cpp

@@ -1152,10 +1152,13 @@ namespace transport
 					msgs.push_back (msg);
 					s += (len + 3);
 					m_SendQueue.pop_front ();
+					if (s >= NTCP2_SEND_AFTER_FRAME_SIZE)
+						break; // send frame right a way
 				}
 				else if (len + 3 > NTCP2_UNENCRYPTED_FRAME_MAX_SIZE)
 				{
 					LogPrint (eLogError, "NTCP2: I2NP message of size ", len, " can't be sent. Dropped");
+					msg->Drop ();
 					m_SendQueue.pop_front ();
 				}
 				else

libi2pd/NTCP2.h

@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2013-2022, The PurpleI2P Project
+* Copyright (c) 2013-2024, The PurpleI2P Project
 *
 * This file is part of Purple i2pd project and licensed under BSD3
 *
@@ -28,6 +28,7 @@ namespace transport
 {
 
 	const size_t NTCP2_UNENCRYPTED_FRAME_MAX_SIZE = 65519;
+	const size_t NTCP2_SEND_AFTER_FRAME_SIZE = 16386; // send frame when exceeds this size
 	const size_t NTCP2_SESSION_REQUEST_MAX_SIZE = 287;
 	const size_t NTCP2_SESSION_CREATED_MAX_SIZE = 287;
 	const int NTCP2_MAX_PADDING_RATIO = 6; // in %