_msg is string (UTF-8) "conv"
_a is string (UTF-8) "123"
_a is number (double) 123
_a is blob (10 bytes) 0x31 0x32 0x33 0x2e 0x30 0x30 0x30 0x30 0x30 ...
_a is number (double) 123
_a is handle 123
_a is number (double) 123
_a is pointer 0x7b
_a is number (double) 123
_a is number (int8) 123
_a is number (int16) 123
_a is number (int32) 123
_a is number (int64) 123
_a is number (uint8) 123
_a is number (uint16) 123
_a is number (uint32) 123
_a is number (uint64) 123
_a is number (char) 123
_a is number (short) 123
_a is number (int) 123
_a is number (long) 123
_a is number (uchar) 123
_a is number (ushort) 123
_a is number (uint) 123
_a is number (ulong) 123
_a is number (float) 123
_a is number (double) 123
_a is string (UTF-8) "123.000000"