Update ZstdInflatingReadBuffer.cpp

src/IO/ZstdInflatingReadBuffer.cpp

@@ -58,6 +58,9 @@ bool ZstdInflatingReadBuffer::nextImpl()
     }
     else if (output.pos == 0)
     {
+        /// It is possible, that input buffer is not at eof yet, but nothing was decompressed in current iteration.
+        /// But there are cases, when such behaviour is not allowed - i.e. if input buffer is not eof, then
+        /// it has to be guaranteed that working_buffer is not empty. So if it is empty, continue.
         return nextImpl();
     }