Represents an incremental variable.

create () returns a new empty incremental variable.

of_value value returns an incremental variable prefilled with the given value.

try_fill ivar value attempts to assign the given value to the incremental variable. Returns true on success and false in case the variable had already been poisoned or assigned a value.

fill ivar value is equivalent to try_fill ivar value |> ignore.

try_poison ivar exn bt attempts to poison the incremental variable with the specified exception and backtrace. Returns true on success and false in case the variable had already been poisoned or assigned a value.

poison ivar exn bt is equivalent to try_poison ivar exn bt |> ignore.

peek_opt ivar either returns Some value in case the variable has been assigned the value, raises an exception in case the variable has been poisoned, or otherwise returns None, which means that the variable has not yet been poisoned or assigned a value.

read ivar waits until the variable is either assigned a value or the variable is poisoned and then returns the value or raises the exception.

read_evt ivar returns an event that can be committed to once the variable has either been assigned a value or has been poisoned.