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@ -525,6 +525,30 @@ Router Class
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and router, and responds to function calls identically to children
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created using other methods.
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For long-lived processes, :py:meth:`local` is always better as it
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guarantees a pristine interpreter state that inherited nothing from the
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parent. Forking should only be used in performance-sensitive scenarios
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where short-lived children are spawned, and only after accounting for
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all the bad things possible as a result of, for example:
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* file descriptors open in the parent remaining open in the child,
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causing the lifetime of the underlying object to be extended
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indefinitely by the child. For example:
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* From the perspective of external components, this is observable
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in the form of pipes and sockets that are apparently never closed
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by the remote end (your program).
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* Descriptors that reference large temporary files will not have
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their disk space reclaimed until the child exits.
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* third party package state (such as urllib3's HTTP connection pool)
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attempting to write to file descriptors shared with the parent.
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* memory mappings for large files that cannot have their space freed on
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disk due to the mapping living on in the child.
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* thread locks held in the parent producing random deadlocks in the
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child.
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The associated stream implementation is
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:py:class:`mitogen.fork.Stream`.
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