Struct TraceWriter 

pub struct TraceWriter { /* private fields */ }

Buffered, flush-on-drop trace writer.

Events accumulate in memory; flush (called on drop, or explicitly) writes the buffered JSON array to disk. Disabled via the special “no-op” constructor for builds where FERRUM_TRACE_OUT is unset — push becomes a no-op so probe call-sites can call into the writer unconditionally.

Implementations

impl TraceWriter

pub fn from_env() -> Self

Construct from env var FERRUM_TRACE_OUT. If unset or empty, returns a disabled writer whose push is a no-op.

pub fn from_env_vars<I, K, V>(vars: I) -> Self

where I: IntoIterator<Item = (K, V)>, K: Into<String>, V: Into<String>,

pub fn enabled(out_path: PathBuf) -> Self

pub fn disabled() -> Self

pub fn is_enabled(&self) -> bool

True if the writer is configured to emit. Probes can use this to skip the BackendTimer overhead entirely when tracing is off.

pub fn push( &self, name: impl Into<String>, cat: impl Into<String>, dur_ms: f64, tid: u32, )

Record a complete event with name, cat, elapsed milliseconds. tid should identify the layer / sub-op (0 for top-level engine).

pub fn push_with_args( &self, name: impl Into<String>, cat: impl Into<String>, dur_ms: f64, tid: u32, args: Map<String, Value>, )

Same as push, but with structured args (e.g. tensor shapes).

pub fn flush(&self) -> Result<()>

Write the buffered events out as a JSON array. Subsequent push calls are buffered into a new file (caller responsibility — flushed writers reset their event buffer).

Trait Implementations

impl Drop for TraceWriter

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.