trace() Default Format
If the trace() function is used to capture data rather than printf(), the
dtrace command formats the results using a default output format. If the data
is 1, 2, 4, or 8 bytes in size, the result is formatted
as a decimal integer value. If the data is any other size and
is a sequence of printable characters if interpreted as a sequence of bytes,
it will be printed as an ASCII string. If the data is
any other size and is not a sequence of printable characters, it will
be printed as a series of byte values formatted as hexadecimal integers.