Trace class:
  Stream class (ID 0):
    Supports packets: Yes
    Packets have beginning default clock snapshot: Yes
    Packets have end default clock snapshot: Yes
    Supports discarded events: Yes
    Discarded events have default clock snapshots: Yes
    Supports discarded packets: Yes
    Discarded packets have default clock snapshots: Yes
    Default clock class:
      Name: _default
      Frequency (Hz): 1,000,000,000
      Precision (cycles): 1
      Offset (s): 0
      Offset (cycles): 0
      Origin is Unix epoch: No
    Event class `ev` (ID 0):
      Payload field class: Structure (1 member):
        dbl: Real (Double precision)

[Unknown]
{Trace 0, Stream class ID 0, Stream ID 0}
Stream beginning:
  Trace:
    Stream (ID 0, Class ID 0)

[0 cycles, 0 ns from origin]
{Trace 0, Stream class ID 0, Stream ID 0}
Packet beginning:

[0 cycles, 0 ns from origin]
{Trace 0, Stream class ID 0, Stream ID 0}
Event `ev` (Class ID 0):
  Payload:
    dbl: 17283.388100

[0 cycles, 0 ns from origin]
{Trace 0, Stream class ID 0, Stream ID 0}
Packet end

[Unknown]
{Trace 0, Stream class ID 0, Stream ID 0}
Stream end