="CommandCompletions.AsyncCommandCompletionHandler.html" title="interface in co.aikar.commands">CommandCompletions.AsyncCommandCompletionHandler</a>&lt;<a href="CommandCompletions.html" title="type parameter in CommandCompletions">C</a>&gt;&nbsp;handler)</span></div>
<div class="block">Registr a completion handler to provide command completions based on the user input.
 This handler is declared to be safe to be executed asynchronously.
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 Not all platforms support this, so if the platform does not suppor