Write-only map interface (i.e. a drain into which key-value pairs can be "sunk")
Removes all key/value pairs from the IMap object.
Returns true if an element in the map object existed and has been removed, or false if the element did not exist.
Sets the value for the key in the map object (the return value is boolean in BTree but Map returns the Map itself.)
Write-only map interface (i.e. a drain into which key-value pairs can be "sunk")