Does HC-05 module buffers the data received?
I didn't find any help in any data-sheets I could find, either. So I'd suggest a simple experiment, sending increasingly large packets before the other side attempts to read anything, until some data goes missing. The packets don't even need to be very sophisticated if all you want to know is whether N_received == N_sent and for what maximum 'N'.
Update:

All bytes were received correctly if there is no delay but with
increasing delay in reading from HC-05 data was not fully received and
with delay greater than 800ms only 63Bytes were received.

If you're collecting data as it arrives, then you can't measure the buffering. When you wait until all data has been set before you try to read any, the number of bytes you receive is the buffer size. It sounds like a 63 byte buffer, probably only what the HC-05's hardware UART can buffer, without using any of its memory to increase that.