message: Add doctests for span macro
diff: @@ -112,6 +112,32 @@ macro_rules! static_meta {
  )
  }
  +/// Constructs a new span.
  +///
  +/// # Examples
  +///
  +/// Creating a new span with no fields:
  +/// ```
  +/// # #[macro_use]
  +/// # extern crate tokio_trace;
  +/// # fn main() {
  +/// let span = span!("my span");
  +/// span.enter(|| {
  +/// // do work inside the span...
  +/// });
  +/// # }
  +/// ```
  +///
  +/// Creating a span with fields:
  +/// ```
  +/// # #[macro_use]
  +/// # extern crate tokio_trace;
  +/// # fn main() {
  +/// span!("my span", foo = 2, bar = "a string").enter(|| {
  +/// // do work inside the span...
  +/// });
  +/// # }
  +/// ```
  #[macro_export]
  macro_rules! span {
  ($name:expr) => { span!($name,) };
  