labelWidget label; interactive widgets also use it for ID generation. A ## suffix can distinguish IDs without displaying the suffix.
p_openOptional open state in Uint8Array[0]. Write only 0 (closed) or 1 (open); the close button writes 0. Null omits the close button. The native call accesses this writable backing memory directly.
flagsImGuiTabItemFlags options controlling this operation; combine compatible flag bits with |.
True when the tab is selected and its contents should be submitted, not merely when the tab exists. Call EndTabItem() only when true.
Begin a tab item and report whether it is selected.